Armin Ronacher

Recently projects started using jQuery for middlewares that rewrite the request (like debug toolbars and similar stuff). This however breaks if another jQuery library is used on the page or if another library is in use because suddenly the $ or jQuery objects work differently.

However, because jQuery is awesome someone thought about that and added the deep-no-conflict mode. Let me show you a small example about how to use no compatible:

<script type="text/javascript" src="jquery-1.3.2.min.js"></script>
<script type="text/javascript">
  (function($) {
    $(function() {
      $('body').html('jQuery is awesome');
    });
  })(jQuery.noConflict(true));
</script>

If you do this in a middleware inside the anonymous function you have access to your jQuery version you just included as $, but outside of it no trace of jQuery is left. Websites will continue to work in exactly the same way as before. Another word of warning: make sure to give your dom elements a really random class prefix in order to avoid clashes on the DOM level and in the CSS definitions. Also: append to things, not prepend. The latter could break first-child selectors people might use.