The name and content attributes specify properties of the entire page. The value of the name attribute is the property you are setting, and the value of the content attribute is the setting that you want to give this property.

Here you can see a <meta> element where the name attribute indicates that you are going to specify a description for the page, and the content attribute is where this description of the page goes:

<meta name="description" content="Buy computer programming books to
learn HTML, XHTML, JavaScript, ASP.Net, PHP" />

The value of the name attribute can be anything; no restrictions are published in any standards. Therefore, if you need to add your own information about a document and its content, you can use this element. Some predefined values for this attribute that are commonly used are:

The description and keywords properties can be used by programs called crawlers, bots, or spiders, which most search engines use to help index web sites. Therefore, they're worth adding to any web page. These programs go through web sites, adding information to the databases used by the search engines, following links as they come across them, indexing those pages, and so on — this is how search engines manage to index so many sites.

<meta name="description" content="Wrox.com has all the coding and
programming resources you need. Find books, articles, and other IT content,
programmer to programmer (p2p) forums, and free code downloads!" />

<meta name="keywords" content="computer, programming, books, web, asp,
asp.net, C#, vb, visual basic, c++, Java, Linux, XML, professional,
developer, html, html, css, xslt, access, sql, php, mysql" />

<meta name="keywords" content="computer, programming, books"
lang="en-us" />

<meta name="keywords" content="livres, ordinatteur, programmation"
lang="fr" />

<meta name="keywords" content="programmieren, bucher, computers"
lang="de" />

<meta name="robots" content="noindex, nofollow" />

The http-equiv and content attributes are paired together to set HTTP header values. Every time a web browser requests a page, HTTP headers are sent with the request, and each time the server responds sending a page back to the client, it adds HTTP headers back to the client:

Of course, the headers can contain much more information, and using the <meta> tags is one way of adding new headers to be sent with the document. For example, you might want to add a header to indicate when the page should expire (no longer be valid) — which is especially helpful if the document contains things such as special offer prices which you know will expire on a certain date — or to refresh a page after a period of time.

<meta http-equiv="expires" content="Fri, 16 April 2011 23:59:59 GMT" />

<meta http-equiv="pragma" content="no-cache" />

<meta http-equiv="refresh"
content="10;URL=http://www.wrox.com/latest.aspx" />

<meta http-equiv="author" content="Jon Duckett" />

<meta http-equiv="Content-Type" content="ISO-8859-1" />

The scheme attribute is not yet widely supported, although it was created to allow web page authors to specify a scheme or format for a property value. For example, if you are working with dates, you can write them in several ways. In the U.S., the date format is commonly written mm-dd-yyyy, whereas in Europe it is written dd-mm-yyyy. So, you might use the scheme attribute to indicate a date format. In the U.S., you could use the following:

<meta scheme="usa" name="date" content="04-16-1975" />

In Europe, you might use the following:

<meta scheme="Europe" name="date" content="16-04-75" />

The use of the scheme attribute does assume that the processing application understands the value of the scheme attribute and name attribute — and given that the mainstream browsers would not understand this, it would fall upon either a script or a custom application to interpret the use of this element.

Having taken a look at the <meta> element, it is time to start preparing your site for the public to visit.

One of the best ways to ensure a site will work on the majority of browsers is to validate your code and make sure that you have stuck to the rules of the language. A validator will check things such as whether you have closed all tags correctly, that the attributes you have used are actually allowed on that element, and so on. All it takes is for you to miss something as simple as one closing </td> tag and, while the page may look fine on your browser, it will not necessarily work on someone else's computer.

As discussed in Chapter 1, each version of HTML and XHTML has a set of rules that govern that version of the language, known as a DTD or schema. A validator can check whether a web page obeys the rules of that DTD or schema. Therefore, by validating your pages you will know if you have left out a tag or other important part of the markup. It is the DOCTYPE declaration at the start of your page that will tell a validation tool which DTD or schema your page should match the rules of.

The W3C (the body that oversees development of HTML, XHTML, and CSS) has a free online validation tool at http://validator.w3.org/. It allows you to enter a URL for a site or upload a page from your computer as shown in Figure 13-1.

Figure 13.1. Figure 13-1

It will then tell you if there are errors in your document; you can see examples of this in Figure 13-2.

Figure 13.2. Figure 13-2

While the W3C validation tool is very helpful — and free — having to validate each page individually can take a while.

Many web page authoring tools, such as Dreamweaver, contain tools that allow you to validate your entire site.

Dreamweaver (which appears to be the most popular authoring tool among web professionals) introduced good validation features for XHTML pages in its Dreamweaver MX version (far better than the validation offered by earlier versions of Dreamweaver). Validating a page is as simple as saving it and then pressing Shift+F6; you should see errors appear in the results panel, asin Figure 13-3.

Figure 13.3. Figure 13-3

For this to work correctly you must have the right settings in Dreamweaver. To get the settings, you can right-click in the results panel and choose the setting dialog box (or Option-click on a Mac). You will then see a whole range of document standards appear in the new Preferences dialog box. You want to make sure that each option is unchecked except the version you want to check against. So, if you are trying to validate Transitional XHTML 1.0, you must have only that box checked, as shown in Figure 13-4.

Figure 13.4. Figure 13-4

It is important to check your links both before your site goes live and after you have published it on the Web. There are several online tools to help you check links; some of them charge, although there are some free link-checking services such as:

You can also use the Link Valet tool to check whether any site you link to has been changed since a specified date. This can be very helpful because an external site might restructure its pages, and the old URL will no longer be valid, or it might start publishing content you no longer wishto link to.

In Figure 13-5, you can see the results of a single page validated with the W3C's link validator.

The results from these services might appear quite verbose, but you should be able to tell which links are bad by looking for some kind of highlighting — which tends to be in red for broken or questionable links.

Figure 13.5. Figure 13-5

Dreamweaver also contains its own link-checking tool. You can access this from the Results menu or by pressing Control+Shift+F9.

There are options to check a page, a folder, or a whole site. Once Dreamweaver has found your broken links you can fix them in either the Results window or the Properties window as shown in Figure 13-6 (or by going into the code for the relevant page).

Figure 13.6. Figure 13-6

Ideally you would already have checked that your color palette had enough contrast to ensure those who suffer colorblindness can still view the site. But if you have not yet done this there are some handy tools here:

Chapter 14 contains a list of techniques to help ensure that your site meets accessibility requirements. This not only helps make sure you reach any potential audience that may suffer from visual or physical disabilities, but also has the benefit that your site is likely to work better on the ever-increasing range of devices that can be used to access the Web.

There are some online tools that help check whether your site meets some of the accessibility requirements, although they cannot check for all aspects of accessibility. For example, these tools can check whether you have used alt attributes on each image, but they cannot tell whether the alternative text will make sense to someone who cannot see the image. Here are two of the online tools that you can use to help check whether your site is accessible:

A very good reference on the topic of accessibility is Web Accessibility: Web Standards and Regulatory Compliance by Jim Thatcher, et al. (Friends of Ed, 2006).

Even if you write your pages to the letter as far as the recommendations go and your pages validate perfectly, different versions of browsers on different operating systems behave differently. The page that looked perfect on your monitor just doesn't look the same on a friend's or colleague's monitor. So, you should always try to test your web page on as many different browsers and platforms as possible. You should, at the very least, have the latest versions of Internet Explorer and Firefox on your computer, and ideally Opera and Safari too.

I would also recommend checking your site in Internet Explorer 6. (At the time of this writing, I was working on a popular web site that still had 16 percent of visitors using IE6, and it does not always show your site as you might expect.) Unfortunately, you are able to install only one version of Internet Explorer on a single computer (unless you have a partition running a second version of Windows or run a Windows emulator), and you are likely to want the latest version for day-to-day use. If you have an old PC lying around, you can keep older versions of browsers on that and use it to test your pages once you have built them. If you need to download an old version of a browser, try http://browsers.evolt.org/.

Another great way to check that a site is working is to ask all your friends to check it before it goes live. At least one or two of them will have different browsers or operating systems, if you're lucky. Ask them to check what it looks like and send you a screenshot of a couple of pages in their browser. If you want to, you can even offer a small prize to one lucky tester as an incentive for them to test your site.

If you are able to, get people who have not been involved in the project to test your site before it is released to the public. This is important because what might seem perfectly obvious to you is not always so clear to someone who is coming to the site for the first time. By the time you have built the site, you will be so close to the designs and workings that it will be very difficult to look at it with the same objectivity as someone who has never seen it.

You want to sit your participants down in front of the site and ask them to perform the tasks. Ideally, the people performing this kind of test on your site would be your target audience.

In Chapter 9, you may remember that we discussed the idea of creating personae that reflect your target audience, and that these actors should have roles that they want to achieve when coming to your site.

You can use these roles again when testing your site. For example, you might have a site that sells bikes and you could ask users to complete the following tasks:

You should only ask each tester to perform around five tasks; any more than this and they will be getting used to the layout and operation of the site.

You should just watch what the users do. You must resist all temptation to intervene at any point, even if you want to ask what someone is trying to do or want to tell them how to get to something you think they are trying to find. (As soon as you start talking to them, you affect their normal behavior — and you won't learn as much.)

Watching where people go to achieve these tasks, how long they spend on each page, and how they navigate can teach you a lot about your site.

Some people prefer to watch silently while participants perform these tasks. Others ask participants to talk their way through what they are doing. In this second scenario (sometimes known as the talking-aloud protocol), you need to make sure that users talk their way through every thought process. You often get broken sentences, but you can get an idea of what you expect of them by performing the task first yourself on a different site. Here is an example of a transcript you might end up with:

You could consider setting up a video camera over the user's shoulder so that you can see the screen and also record their voice, as long as it doesn't put the user off too much. Again you must resist the temptation to interrupt if users are doing something that is not what you think they should be doing in order to achieve the task — after all, in this example you learned that the user expected to be able to click on the image of the bike to see more details, but couldn't.

If you have the time and budget, then there is a lot more you can do in terms of testing. But many web developers avoid doing any testing because they feel that they do not have the time and budget, and if you find yourself in this situation, you can find out a lot about your site and how it will be used by simply watching a small group of people perform basic tasks.

If you are working on a commercial site, it can often help to hire a proofreader to check all your text. Silly typos can affect people's impression of the site you built and make both you (and the client, if you are developing the site for someone else) look less professional.

If your client finds errors throughout the site, you appear careless — even if the client supplied the error-ridden copy for the site.

The domain name is the part of the web address you commonly see after the letters www. For example, Wrox Press uses the domain name wrox.com, whereas Amazon uses the domain name amazon.com in the U.S., amazon.co.uk in the U.K., amazon.de in Germany, and so on.

You can register your domain name with a domain registration company, of which there are hundreds; just search on your favorite search engine and you will find plenty. Most companies go for the suffix .com, but several other suffixes are available. For example, there are country-specific domain suffixes (also known as top-level domains) such as .co.uk for the UK, .de for Germany, .com.au for Australia, and .ru for Russia. You should choose a country-specific domain only if you are based in that country. Indeed, some domain names can only be bought by people with registered companies in that country. Then there are also suffixes such as .me.uk, which is for personal sites; .info, which is for information-based sites; and .org, which is for registered organizations. (Unless you are working for a large multi-national corporation, you do not need to purchase all available suffixes for your domain name.)

Before you register your name, you need to see if it is available; all domain name registration companies should have a form that allows you to search to see if your domain name is available. You might find this a frustrating process, as an incredibly high proportion of the .com domain names you might think of have been taken already, as well as most popular words (even combinations of popular words).

You might also like to check that the name of your site is not very similar to that of someone you would not want to be associated with, just in case the user mistypes the URL. For example, you would not want a children's site to have a very similar URL to an adult-content site.

You can order your domain name without actually having a site ready; this is known as domain parking. You order the name as soon as you know you are going to create the site (after all, you will probably want to use the URL in the site design, and will therefore need to order it before you start designing the site), but you do not put anything up there until you have built the site.

Several domain-name registration companies also offer hosting (hosting is covered in the next section), but you do not (generally speaking) have to order your domain name from the same people that host your site. You can get the domain name registration company to point the domain to your hosting company's servers (usually there is a control panel on the site you registered the name with where you specify where your domain name actually points).

Your domain name should be easy to remember. Avoid names that are so long that users will find them hard to remember or too long to type in. For example, if you were called the Sydney Slate Roofing Services Limited, you might choose a domain such as www.SydneySlate.com rather than www.SydneySlateRoofingServicesLimited.com.

When you register the domain name, you will also be able to use this for your e-mail addresses. For example, if you choose the domain www.example.com, then no one else will be able to use the e-mail address [email protected] without your permission. (Unfortunately, it is possible for spammers to make e-mails appear as if they come from your domain, simply by changing the "from" address in their e-mail programs, and there is nothing you can do to prevent this.)

You already know that in order to view a web page, a browser requests a page from a web server. The web server is a special computer that is constantly connected to the Internet.

When you access a page using a domain name, such as www.example.com/, something called a name server changes the name into a number. The number (known as an IP address) uniquely identifies a machine on the Web and this machine holds your web site.

So when you are ready to put your site out on the Web, you are going to need some space on a web server. Hundreds of companies will allow you to put your web site on their servers and will, of course, charge you for the service. The service is known as web hosting because the company hosts your site for you.

Some ISPs will give you a small amount of web space free when you choose them to access the Internet. There are also other sites that offer free hosting (these are often paid for by the use of pop-up advertisements that appear when your pages load). For a personal site you may need only a small amount of web space and you might be prepared to put up with any pop-up ads that come with the free service. For commercial sites, however, it is better to choose some paid hosting — which can still be very cheap but will not serve advertisements.

As I said, literally hundreds of companies offer web hosting, and it can seem like a minefield deciding which to go with. Following is a discussion of the key points you need to understand and consider when choosing a site (these points are listed here in alphabetical order, rather than in order of importance):

Unless you are a running a very large company, it is rarely worth the investment of running your own servers because you are likely to need someone capable of administering the machines and taking care of them on a regular basis. If you decide that you do need your own dedicated servers, several hosting companies will manage a server on your behalf, updating it with new patches for the operating system to fix security holes when needed — this is known as a managed dedicated server. While this is still expensive, you will generally find it cheaper than hiring someone yourself to manage your servers.

Once you have paid for some space on a web server, you need to be able to get the files that make up your web site onto this computer — which can be on the other side of the world. The most efficient way to do this is using FTP.

FTP stands for File Transfer Protocol. The Internet uses a number of different protocols for sending different types of information. For example, HTTP (Hypertext Transfer Protocol) is used for transmitting hypertext files, which are better known as web pages (that's why most web addresses start with http://). FTP is a protocol used to transfer binary files across the Internet and is much quicker at sending whole web sites to a server than HTTP.

Most hosting providers actually require that you use FTP to transfer your pages onto their servers, which means that you need an FTP program (sometimes referred to as an FTP client) to put your files on a server.

FTP programs usually have two windows, each with a file explorer. One represents the files and folders on your computer; the other represents the folders on the web server. In Figure 13-7, you can see the folders on my computer, and on the right you can see those on a web server.

Figure 13.7. Figure 13-7

The table that follows shows some of the most popular FTP programs.

Each of the programs is slightly different, but they all follow similar principles.

When you register with a host, this host will send you details of how to FTP your site to its servers. This will include:

Figure 13-8 shows you how these are entered into the FTP program called Transmit on a Mac.

Figure 13.8. Figure 13-8

Some hosting companies allow you to use a variant of FTP called SFTP or secure FTP. This is considered to be more secure than standard FTP because the username and password are encrypted when they are sent to the server. If your host supports this option, it is a good idea to use it.

Because a lot of people develop their first site on a desktop or a laptop computer they often use relative URLs for all links, images, style sheets and scripts, rather than absolute ones (because they do not have a full URL for the site yet). This is very helpful because it means that the links will work on a web server of the hosting company without any changes.

When developing a site on your desktop machine, the address bar of your browser might contain something like this:

C:Documents and Settingsadministratorwebsitesexamplesiteindex.html

But when you are ready to make the switch to the new site, you are going to want it to appear here:

http://www.example.com/index.html

If you are using relative URLs to link to all of your other pages, images, script files, and so on, then moving a site to a new folder or even a new URL will not be a problem. However, if you hard-code your paths, you may find that links, images, and other files do not load. For example, suppose you used an image for the logo of your site, and used the full file path in the src attribute, like so:

<img src=" C:Documents and Settingsadministratorwebsites
examplesitemagesour_logo.gif" alt="Our Logo" />

This image would not be loaded when you move the site to a server. It is better to use something like this:

<img src="images/our_logo.gif" alt="our logo" />

Now, as long as the images folder is within the directory that this page lives in, the image will be loaded, no matter where the site is moved.

Now that your site is on the server where the public can see it, you should check your pages thoroughly again to ensure they appear as you intended. Remember to check that all of the links work and that the images and other files are loading. You should consider running a link checking tool (like the ones discussed earlier in this chapter) again to help check whether links are working. Once you are happy that the site is functioning properly, you can start to tell the world about it.

The first thing to do is to mention your URL wherever you can. For a start, if you have any printed material, from business cards and letterheads to brochures, posters and adverts, include your URL on them. Likewise, ensure that you have it on your e-mail signature.

Entertaining or informative content is one of the best reasons for people to come to your site. If you are able to, creating regular content not only gives people more reasons to come to your site (because you are regularly adding new material that may be of interest to new people), but it also gives people who have found your site a reason to come back regularly.

If you want people to come back regularly, it is important to give people an idea of how often the site is updated. This can be done through some fairly simple means such as adding the date that the items are published under headlines (as you see on many blogs), or by spelling out how often the site is updated.

If you have any particularly interesting or noteworthy news that you think would benefit from a Press Release, then you can consider writing one and submitting it to a PR news service such as PR Web (www.PRweb.com). Other journalists and bloggers may pick up on your article and mention it.

Some site owners will allow other web sites to republish content that they have written in return for a link back to their web site. If you want to do this you can tell visitors that this is an option at the bottom of your articles, and go out and offer your content to other sites.

Many industries and hobbies have their own forums and online communities. You can also find groups of people interested in the same topic on social networks, such as Facebook and LinkedIn.

If you become a part of any online community that is relevant to your site, you can build your profile amongst the community. By having your URL on the signature and profile page of sites you post to, or on your social network profile pages, more people become aware of your site, and they may be regularly reminded of it.

It is very important when becoming part of an online community that you do not just post messages when you have something to say about your site or have added something new to it. As with any community you should get involved in the conversations and reply to other people's posts offering advice where you can (giving back to the community, not just using it to promote your site).

Many trades and hobbies have at least one site that lists all other sites in that field. Try to find out if there are any sites that relate to the subject of your site and ask those sites to link to you.

Some trade directories charge for listings; if this is the case ask their monthly traffic and average number of visits you can expect per month from your listing before handing over any money. You may then want to suggest a trial period before handing over a full year's subscription (you will see how to track how many people come from such sites shortly).

Many smaller sites offer reciprocal links; that is, they will link to you in return for your linking to them. It is a way for everyone to boost traffic. If you do this, make sure that you are not putting someone on the front page of your site when they are going to put a link to you tucked away on a page that few people will come across — the term is reciprocal linking, after all.

While it is good to have as many people linking to your site as possible, you will tend to get better trafic from sites that cover topics relating to the subject of your site.

Use a few search engines to search for competing sites or company names and see who is linking to and talking about them — the sites that link to your competitors may well link to you, too, if you ask.

You have probably seen links like those shown in Figure 13-9 on many web pages, encouraging users to bookmark a page on services such as Delicious or Stumble Upon, or to vote for the page on sites like Digg.

Figure 13.9. Figure 13-9

While most of the sites shown in this button in Figure 13-9 will have pages that describe how to link to each of them individually, a far simpler and quicker way to add these options to your site is using a web site called www.addthis.com/(this site provides very simple tools to create a link like this encouraging visitors to share the site with others).

You can also provide a page with buttons or banners that make it easy for other sites to link to you. This is more likely to happen with hobby sites than with commercial ventures, but people who create sites in their spare time will often link to other special-interest sites. If you provide them with attractive images, and show them the code to add the images and links to their site, they are more likely to include these ads. Figure 13-10 shows some examples from the Oxfam web site.

Figure 13.10. Figure 13-10

When you have searched on Google you will probably have noticed the links down the right-hand side of the page like those in Figure 13-11.

Figure 13.11. Figure 13-11

These are examples of what is known as pay-per-click advertisements, so called because the advertiser only pays each time someone clicks on the ad.

Google's pay-per-click advertising system is called AdWords, and in order to advertise, you specify a set of keywords that relate to your site (and create your ad copy). The ad will only appear when someone searches on one of these keywords.

There are two main factors that determine the order in which your advertisements will appear:

This can be a very cost-effective way to generate traffic to your site. Yahoo offers a similar service called Yahoo! Search Marketing, and Microsoft has a system called adCenter.

Display advertising is a term used to describe advertisements where you pay for your ad to appear on a particular site. It is most commonly associated with banner ads.

Companies are charged for display ads in two common ways. First, there is the cost-per-thousand impressions confusingly named CPM (which stands for cost per mille). Second, you may be charged to occupy a space on a page on a per month or per year basis.

If you do take out display advertising it is worth noting that click-through rates on display ads are very low.

Remember that a lot of web users are immune to advertising and just scan pages to find what they really want. If you are going to create a banner, make sure it's visually attractive and gives people a clear incentive for clicking on it. You want people to want to click on your ad so it's worth the money you are spending to have it appear on other sites.

Some current thinking suggests that online display ads are more suited to brand awareness than achieving specific actions such as getting people to visit your site, because click-through rates are very low. It is not uncommon for display ads to have less than 1 percent of the people viewing the ad visiting the site.

If you have regularly changing content, consider adding an e-mail newsletter feature to your site. By encouraging people to sign up for e-mail updates you can regularly remind them about your site and tell them what has changed.

Some good tools for creating and managing e-mail lists are:

Both of these tools not only help you send e-mails to visitors, but also help you create subscription forms so that visitors can easily sign up to your newsletter.

Near the form where people can subscribe to your newsletter, it is a good idea to explain to visitors the incentives for signing up and tell them the benefits of giving you their e-mail address.

You can also consider approaching other complimentary companies to see if they would mention you in their newsletter in return for a mention on yours.

Now that people are coming (you hope) to your site, you can learn a lot about what they are doing on the site and how they found you.

There is an incredible amount of information available, but here are ten things I always look at first when studying a Google Analytics report for a site:

Google Analytics lets you specify the timeframe you want to look at this data for. I find that looking at monthly reports gives me a good overview and starting point for a site's traffic.

You can also instruct it to e-mail you reports on a daily, weekly, or monthly basis, which saves you having to log in to check the statistics each day.

The ability to track where visitors come from using tools such as Google Analytics means that in addition to discovering where people are coming from, you can also measure the success of marketing activity, which allows you to determine the return on your investment (ROI).

In addition to ascertaining whether your marketing investment has paid off in terms of financial cost, you should also consider the time it took you to initiate the marketing activity. For example, you may spend $100 in a month on Google AdWords and it could take you half a day to set it up, write your ads, and check in again a few times while the ads are running. In this instance, it may be more cost-effective to spend 10 minutes writing to a few bloggers who might create a lot more traffic for you at no cost.

So, wherever you can, try to ensure that you are able to measure the performance of each kind of marketing and awareness activity you perform. In addition to looking at referrers, Google Analytics allows you to add the following extra information to your URL so that you can measure the effectiveness of links.

There is a handy tool that Google offers to add these links to your URL — just search for Google Analytics URL Builder. Here is an example of a URL with additions to say that a display advert had been added to www.referrer.com for a campaign about cheddar cheese:

http://www.example.com/?utm_source=referrer.org&utm_medium=display&utm_term
=cheese&utm_content=cheddar&utm_campaign=taste%2Bthe%20cheese

There are lots of companies and individuals who create software that you can use on your web site: blogs, message boards, content management systems, e-mail newsletters — the list is (almost) endless. They allow you to add complex features to your site that would take a lot of time and experience to create yourself. Many web design firms use off-the-shelf software, and customize it for their clients (rather than building applications from scratch).

You may find some of these tools will help you create a more advanced web site, and what you have learned in this book will help you take control of the appearance of these tools and make them fit in with the sites you design.

Generally the tools discussed in this section are provided in one of two ways (or sometimes both):

Some companies charge for a license to use the software on your site, but there are also a lot of free options out there.

Many hosting companies will allow you to add some of the software discussed in this section to your site using what are known as "one-click-installations," where you only need to press one button on the control panel for your web site to have them install the tools.

This section provides an introduction to some other technologies, what they can do, and how you can make use of them on web sites. I hope this helps you decide what technology you might want to start learning next when you have gained experience with everything you've learned in this book.

Server-Side Web Programming: ASP.NET and PHP

You've already seen the very basics of what a programming language such as JavaScript can do in a browser, but when a programming language is used on a web server, it becomes even more powerful.

Any time you want to collect information from a visitor to your site and return a page that is customized for that visitor, you will want to look at server-side programming. Here are some examples of applications where different users will need different pages:

• Shopping online: Users browse through a catalog of products and select which ones they want. Their choices are often reflected in a shopping basket displayed on each page. After they have chosen what they want, they provide their payment details and contact/delivery details. At the same time, the people running the store are likely to have a browser-based interface that allows them to add new products to the site (rather than having to create each new page and link to it individually).

• Checking train times: The user enters the point he or she is traveling from and the destination, along with preferred travel times. The application then creates a page that contains the requested journey times.

• Discussion boards and forums: The examples you have already seen mentioned in this chapter of discussion boards and forums rely on another company's server-side programming and code to handle all of the posts.

• Searching for content on a site: The user enters a term into a form that he or she wants to search, which is then sent to the application on the server. The application creates a page that contains results the user inquired about.

One thing that all these types of applications have in common is that the scripts on the server are being used to store information in, and read information out of, a database. (You can think of a database being a little like a set of spreadsheets where information is stored for use in many kinds of applications.) You will learn more about this shortly in the section "Content Management."

Choosing a Server-Side Language

You can work in several different server-side languages and environments, such as ASP.NET and PHP, both of which offer very similar capabilities. Generally speaking (although there are exceptions to the rule):

• ASP.NET runs on Microsoft IIS and Windows servers.

• PHP runs on UNIX servers.

You can code these pages on your desktop computer with the right software installed, but you will want to host the finished web site on a web server.

The first applications created using a script on a server were known as CGI scripts. You may still see CGI or CGI-bin in the URL of some applications. However, the languages discussed here are in far higher demand.

Different developers will have different opinions about which language to choose. Most people learn one language and environment and stick to it (although to a certain degree it is much simpler to learn a second language and environment when you already understand one and know what can be done with server-side scripting languages).

If you are learning a technology in order to get a job, then it's a good idea to keep an eye on job advertisements. You will be able to track the technologies employers are asking for and also (if you look regularly) you will be able to see the emerging technologies early on — first there will be only one or two mentions of these technologies, and then the mentions will come more regularly. Job ads can therefore be quite a good barometer for technologies you should consider learning. (And if your boss catches you looking at job ads, you've got a great excuse — you're just researching which technologies are going to be more popular in the near future.)

Content Management

One of the key aspects of many sites is a content management system. This is actually a fancy name for something that will allow you to easily update the content of your web site without actually having to create a new page for each new article, posting, or product for sale.

Content management systems tend to be based on a relational database. Relational databases contain one or more tables, each of which is like a spreadsheet. Figure 13-13 shows you a database used on a site about music. (This "example" site is adapted from an actual one.)

Figure 13.13. Figure 13-13

You can see that there are several rows in this table, each containing the details of a different advertisement. The columns each contain different information about the article in that row:

• articleid is a number used to uniquely identify each article in the system.

• posted is the date the article was posted.

• lastupdate is the date that the article was last updated.

• headline is the headline for the article.

• headlinedate is the date that the article says it was written on.

• startdate is the date the article should be published on.

• enddate is the date that the article should stop being available on the site (several of the articles have the date set to the 31 December 9999 — so if the site is still around then, the managers will have to do something about the dates, but until then the article will remain published).

This table actually contains a lot more fields, but this gives you an idea of how the information is stored. When users come to the site that uses this database, they will navigate through categories to find the items they are interested in. Rather than having a page containing the details of each article, the site contains only one page that displays all news articles, called article.aspx. This is like a template for all the articles, and the title, headline date, and article are added into the page at the same place in each article. You can see an example of an article in Figure 13-14.

Figure 13.14. Figure 13-14

The structure of the URL for this article is the key to how this template-based system works:

http://www.example.com/news/features/article.aspx?a=1496

The article.aspx page is requested, and when it is requested, the article identifier 1496 is also requested. This corresponds with the number in the first column of the table in Figure 13-13. All the details of this article are then placed into the template. So, where the text says "Thursday December 6, 2007" this is the headline date field from the database.

Some sites contain the headlines in the URL rather than an article ID, for example:

http://www.example.com/news/features/Interview-Duffy-(no-not-the-bass-player-in-GnR)

Here you can see that the title of the article is used in the URL rather than the ID, which is known as URL rewriting. Behind the scenes, the URL is compared to the database, and it will know to return the article whose headline matches the end part of the URL.

This approach is also what makes it possible for many authors to update the same site without having to know how to code each individual page. They simply log into an administration tool that allows them to submit articles using a simple form. Figure 13-15 shows one of the pages that enables users to enter new articles.

Figure 13.15. Figure 13-15

This approach of storing content in a database is employed in many different types of sites. For example, auction sites such as eBay store each item for sale in a row of a database; likewise, e-commerce stores tend to store product details in a database, with each product stored in a row of one of the tables. When these sites use a row of a table for each article or product, new articles or products can be added to the database using XHTML forms (rather than having to hand-code pages or manually update the database).