AJAX - Browser Support

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All the available browsers cannot support AJAX. Here is a list of major browsers that support AJAX.

  • Mozilla Firefox 1.0 and above.
  • Netscape version 7.1 and above.
  • Apple Safari 1.2 and above.
  • Microsoft Internet Explorer 5 and above.
  • Konqueror.
  • Opera 7.6 and above.

When you write your next application, do consider the browsers that do not support AJAX.

NOTE − When we say that a browser does not support AJAX, it simply means that the browser does not support the creation of Javascript object – XMLHttpRequest object.

Writing Browser Specific Code

The simplest way to make your source code compatible with a browser is to use try...catch blocks in your JavaScript.

<html>
   <body>
      <script language = "javascript" type = "text/javascript">
         <!-- 
         //Browser Support Code
         function ajaxFunction() {
            var ajaxRequest;  // The variable that makes Ajax possible!

            try {
               // Opera 8.0+, Firefox, Safari 
               ajaxRequest = new XMLHttpRequest();
            } catch (e) {

               // Internet Explorer Browsers
               try {
                  ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
               } catch (e) {
                  
                  try {
                     ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
                  } catch (e) {

                     // Something went wrong
                     alert("Your browser broke!");
                     return false;
                  }
               }
            }
         }
         //-->
      </script>
      
      <form name = 'myForm'>
         Name: <input type = 'text' name = 'username' /> <br />
         Time: <input type = 'text' name = 'time' />
      </form>
      
   </body>
</html>

In the above JavaScript code, we try three times to make our XMLHttpRequest object. Our first attempt −

  • ajaxRequest = new XMLHttpRequest();

It is for Opera 8.0+, Firefox, and Safari browsers. If it fails, we try two more times to make the correct object for an Internet Explorer browser with −

  • ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
  • ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");

If it doesn't work, then we can use a very outdated browser that doesn't support XMLHttpRequest, which also means it doesn't support AJAX.

Most likely though, our variable ajaxRequest will now be set to whatever XMLHttpRequest standard the browser uses and we can start sending data to the server. The step-wise AJAX workflow is explained in the next chapter.

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