<!-- Another way to put jQuery into no-conflict mode. --> <script src="prototype.js"></script> <script src="jquery.js"></script> <script> jQuery.noConflict(); jQuery( document ).ready(function( $ ) { // You can use the locally-scoped $ in here as an alias to jQuery. $( "div" ).hide(); }); // The $ variable in the global scope has the prototype.js meaning. window.onload = function(){ var mainDiv = $( "main" ); } </script>