Designing Applications That Work on Web Clients

The Domino database is the application container, an object store containing various types of Notes documents, including design elements and many other types of data described throughout this book but covered in detail in Chapter 4, “Design Elements.” A major advantage to accessing the Domino server with a Web browser is that users are using generic Web browser clients. If the HTTP task is running on the Domino server, Domino provides the HTTP interface for Internet clients. Although some of the Notes client functions are not available, there is no need to install a Notes client on the user's system. Unlike traditional Web site design, where Web pages, images, data, and so forth are stored in hierarchical file structures, Domino stores information within the Notes database object store. Special Uniform Resource Locator (URL) commands are then used to access these design elements.

For users to access an HTML application in the Web browser, they simply enter the URL of the Domino server and the address of the Domino database as the Internet address. Unless a specific design element is passed in the URL address, the database opens to the design element specified in the Launch tab of the Database Properties dialog box.

If you are a Web developer or an experienced Notes developer beginning to develop applications for Web users, Domino 6 extends many of its most useful capabilities to the Web. More importantly, it also enables developers to use Web technologies within the Domino Designer IDE. Therefore, languages such as JavaScript and Java can be written directly to the properties and methods of the objects and compiled (if Java) from within Notes. Domino fully supports HTML 4, JavaScript, the Document Object Model (DOM, not to be confused with the Domino Object Model) as defined by the World Wide Web Consortium (W3C), XML, Cascading Style Sheets (CSS), Java, Java Servlets, Java Libraries, and JSP tag libraries. Domino Designer also supports CORBA/IIOP in the creation of distributed applications. CORBA/IIOP allows designers to write Java applications and Java applets that can remotely access Domino servers and data stored in Domino databases. Integrating these Web languages into the Designer IDE enables developers to more easily, quickly, and accurately build sophisticated applications.

You can preview the design of the design elements with either Internet Explorer 4.x or higher, or Netscape 3.x, 4.x, or higher. If the browsers are registered on the current system (in the Registry file), icons appear in the design toolbar (see Figure 13.1).

You can also preview the current design element by selecting Design, Preview in Web Browser, and then selecting Default Browser, Notes Browser, Internet Explorer, or Netscape Navigator.

Troubleshooting when developing and designing applications for the Web is covered in detail in Chapter 14 (“Design Elements”). Nevertheless, keep in mind that the most obvious way to troubleshoot Web applications is to preview the Web page during design. To test your Web design elements with a Web browser, select the Preview in Web Browser options from the Design pull-down menu. This automatically launches the browser specified in the current location document so that you can preview the current design element. When previewing local databases, Notes launches the Local Web Preview application.

Because you may be designing applications to run on Internet Explorer as well as on Netscape, you can run the JavaScript debugger in JavaScript to help debug JavaScript code. If using Netscape (or Mozilla), simply type JavaScript: in the URL field within the browser. This launches a separate JavaScript window. Now, when the browser encounters JavaScript errors on the pages it loads, they are automatically written to the JavaScript debugger window, and the potential error is highlighted.

Java and JavaScript are both case sensitive, so check that errors are not a result of incorrect case. HTML and LotusScript are not case sensitive.

Many Domino design elements are supported for native Notes clients and Web clients. However, some of the design elements could not be simulated for Web clients within the capabilities of HTML. Therefore, some of the design elements are now available to Web clients as Java client-side applets. Four applets are available:

• Embedded Outline— Customizable site navigation.

• View or Embedded View— A view embedded on a page or form, providing a customizable interface for displaying and interacting with lists of documents and other objects. Supported by either Notes or Web clients.

  With embedded views on the Web, the view can be set to display a single category, and the number of lines to display can be controlled. Single-category views can be determined by hard-coding the category value or can be dynamically determined. Single-category views do not work in native Notes. When tested, it works in both clients.

  
  

• Text Editor— A fully functional, rich-text editor for creating and editing content.

• Action Bar Applet— Displays action on the Web (these buttons roll over and drop down menu options)

For more information on using these and other design elements, refer to Chapter 9, “Design Elements.”

Another feature that is important when developing Web applications is the support of Common Object Request Broker Architecture (CORBA). Prior to R5, the back-end classes (previously referred to as the Notes Object Interface or NOI) were not available to the browser. Only the server could access these objects and then serve HTML to the browser, or accept the browser submission and process the user's request when saving. Now the back-end classes contained within the Domino Object Model (DOM) are available to the browser without requiring that you open or save the document with Java or JavaScript supporting W3C standards.

Since R5, you can import HTML files and/or cut and paste any elements from an existing Web page, and Domino preserves the full fidelity of the HTML page, including applets, animated GIFs, and so on. After these pages are imported or pasted, they can be displayed within the Designer or within Notes clients.

Text created on either forms or pages for Web applications can be entered by either of the following methods:

• Import text from an existing HTML file.

• Enter text directly onto the page or form (you can optionally use the new HTML pane when entering HTML directly on a page or form).

When importing text from an HTML file, the designer translates the imported HTML and renders the result on the Designer page or form. To import HTML, follow these steps:

1.	Open a page or form in the Designer client.
2.	Position the cursor in the desired location of the HTML.
3.	Select File, Import from the pull-down menu
4.	Select the HTML file (.HTM or .HTML).
5.	Click Import.