function bindJQuery() {
  var originalCleanData;

  if (bindJQueryFired) {
    return;
  }

  // bind to jQuery if present;
  var jqName = jq();
  jQuery = isUndefined(jqName) ? window.jQuery :   // use jQuery (if present)
           !jqName             ? undefined     :   // use jqLite
                                 window[jqName];   // use jQuery specified by `ngJq`

  // Use jQuery if it exists with proper functionality, otherwise default to us.
  // Angular 1.2+ requires jQuery 1.7+ for on()/off() support.
  // Angular 1.3+ technically requires at least jQuery 2.1+ but it may work with older
  // versions. It will not work for sure with jQuery <1.7, though.
  if (jQuery && jQuery.fn.on) {
    jqLite = jQuery;
    extend(jQuery.fn, {
      scope: JQLitePrototype.scope,
      isolateScope: JQLitePrototype.isolateScope,
      controller: JQLitePrototype.controller,
      injector: JQLitePrototype.injector,
      inheritedData: JQLitePrototype.inheritedData
    });

    // All nodes removed from the DOM via various jQuery APIs like .remove()
    // are passed through jQuery.cleanData. Monkey-patch this method to fire
    // the $destroy event on all removed nodes.
    originalCleanData = jQuery.cleanData;
    jQuery.cleanData = function(elems) {
      var events;
      for (var i = 0, elem; (elem = elems[i]) != null; i++) {
        events = jQuery._data(elem, 'events');
        if (events && events.$destroy) {
          jQuery(elem).triggerHandler('$destroy');
        }
      }
      originalCleanData(elems);
    };
  } else {
    jqLite = JQLite;
  }

  angular.element = jqLite;

  // Prevent double-proxying.
  bindJQueryFired = true;
}