AJAX provides dynamic webpages in which the user and server communicate in the background rather than loading the entire page. It is critical to understand browser compatibility since various browsers implement the XMLHttpRequest object and its associated attributes and functions differently.

The following important points are used to assess the compatibility of the browser:

Support the XMLHttpRequest object: The XMLHttpRequest object must be supported by a browser. Some older browsers, such as Internet Explorer 6 or previous iterations, do not retain the XMLHttpRequest object. You will need to employ the fallback method, which uses iframe or form elements to perform all the AJAX features, in order to make them compatible with different browsers.

Cross-origin request: XMLHttpRequest-based cross-origin requests are not supported by all browsers. Therefore, we employ CORS (Cross-Origin Resource Sharing), JSONP (JSON with padding), or proxy servers to do cross-origin queries in order to mitigate these vulnerabilities.

Response Type: For XMLHttpRequest, different browsers may support various response kinds, such as text, JSON, XML, binary data, etc. Therefore, you must identify the supported response type and manage it carefully if you want your application to work with a variety of web browsers.

Error handling: XMLHttpRequest errors are handled differently by various browsers. Therefore, be sure that your error handling code is compatible with all browsers.

Event Handling: Various browsers may handle XMLHttpRequest events, such as onload, in different ways. So you need to test and then adjust your code to ensure that it works well for all browsers.

Even so, AJAX is fully supported by the majority of contemporary browsers, including Google Chrome, Mozilla Firefox, Microsoft Edge, Safari, and Opera. However, certain older browsers, such as Internet Explorer 6 and 7, only partially support AJAX. Therefore, keep in mind that browser compatibility will have an impact on how the AJAX web application operates.

Conclusion

You must utilize a JavaScript library or framework that offers cross-browser support for AJAX if you want your application to operate with every browser. Additionally, these libraries provide a standard API for the AJAX request and assist you in eliminating browser-specific variations while processing XMLHttpRequest. The security features offered by AJAX will now be discussed in the next article.

AJAX: Example

Here is a list of some well-known online apps that employ AJAX.

Google Maps

Instead of clicking on a button, a user may drag a complete map using the mouse.

Google Suggestions

Google makes recommendations as you write. To traverse the results, use the arrow keys.

Gmail

Gmail is a webmail service based on the notion that emails may be more user-friendly, effective, and practical.

Yahoo Maps (new)

Reaching your destination is now considerably simpler and more enjoyable!

The distinction between a traditional CGI program and AJAX

You’ll notice a difference if you try these two instances one at a time. When you attempt the normal GCI example, you have to wait for the answer and your site is refreshed, but when you try the AJAX example, there is no discontinuity and you receive the response extremely soon.

AJAX: Support for Browsers

Not every browser on the market can handle AJAX. The main browsers that support AJAX are listed below.

  • 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.

Don’t forget to account for browsers that don’t support AJAX when creating your next application.

NOTE: The term “browser does not support AJAX” refers to the browser’s inability to create Javascript objects or XMLHttpRequest objects.

Writing Code That Is Specific to a Browser

Try…catch blocks in JavaScript are the easiest approach to make your source code browser-compatible.

Example

<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>

Output

We attempt to create our XMLHttpRequest object three times in the JavaScript code above. Our initial effort—

ajaxRequest = new XMLHttpRequest();

It is compatible with Firefox, Safari, and Opera 8.0+. If that doesn’t work, we attempt twice more to create the proper object for an Internet Explorer browser using −

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

If it doesn’t work, we can use a really old browser that doesn’t support AJAX since it doesn’t support XMLHttpRequest.

However, we can now start sending data to the server because our variable ajaxRequest will probably be set to whatever XMLHttpRequest standard the browser employs. The next chapter provides an explanation of the step-by-step AJAX procedure.

Post Views: 0

Categorized in:

JavaScriptjQuery