In most cases, if we've encountered an error, we normally stop further execution of the script. It is logical to do that in most scenarios. For example, if we have a problem loading the required URL or file, we halt the process since we reference DOM objects within the page after loading; we cannot do so if the page is not available.

The PhantomJS exit function can accept a numeric value that will be used as the error code; it is used by calling the shell script.

else {
  console.log('Ooops! Problem loading page.'),
  phantom.exit(1);
}

In the preceding code, we call the phantom.exit method and pass a value of 1; this will denote our exit code that, within our script, means the page is not loaded. We can return different exit codes for different problems as we see fit.