How can the right part of page of Google videos stay still when you search videos on the left

Question

When you use Google Videos, you will notice the right part of the page stays still when you search videos on the left. How is it implemented?

Answer 1

using ajax

http://www.google.com/search?q=ajax+tutorial

edit:

function $(id) { return document.getElementById(id); }

function getHTTPObject() {
  var xmlhttp;
  /*@cc_on
  @if (@_jscript_version >= 5)
    try {
      xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {
      try {
        xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
      } catch (E) {
        xmlhttp = false;
      }
    }
  @else
  xmlhttp = false;
  @end @*/
  if (!xmlhttp && typeof XMLHttpRequest != 'undefined') {
    try {
      xmlhttp = new XMLHttpRequest();
    } catch (e) {
      xmlhttp = false;
    }
  }
  return xmlhttp;  
}

function AJAX_GetAsinc(ajax, id, url) {
  ajax.abort();
  function statechange() {
    if ((ajax.readyState==4) && (ajax.status==200)) $(id).innerHTML=ajax.responseText;
  }
  ajax.open('GET', url, true);
  ajax.onreadystatechange = statechange;
  ajax.send(null);
}

usage:

var a = getHTTPObject();
AJAX_GetAsinc(a, 'YOUR_DIV_ID', 'mycontent.php');

or:

use jQuery or your favourite framework/library

Hope it's specific enough