November 25, 2006 by nxt

Using AJAX (which implies the use of the XMLHttpRequest) has one big limitation, you can only make requests to the server from where the page was downloaded.
As an alternative you can use javascript to dynamically include other javascript files which should be generated serverside.

An example on how to call the server:

function callServer() {
 var head = document.getElementsByTagName("head").item(0);
 var myTag = document.createElement("script");
 myTag.setAttribute("type", "text/javascript");
 myTag.setAttribute("src",
  "http://example.com/application/getjs/?var1=value1");
 head.appendChild(myTag);
}

The idea is that you generate the javascript that you need by dynamically add another script tag on the page.
for an excellent example of this approach you can read this javaworld article