Load jQuery from Google CDN

load_jq.js

/*
 * @param object callback
 * @param object document context
 * /
function load_jq(callback, document)
{
  if (window.jQuery) {
    if (callback) {
      callback(jQuery);
    }
    return;
  }
  var d = document || window.document;
  var s = d.createElement('script');
    s.onload = function()
    {
      jQuery.noConflict();
      if (callback) {
        callback(jQuery);
      }
  }
  s.setAttribute('src', location.protocol + '//ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js');
  d.getElementsByTagName('head')[0].appendChild(s);
}