Hi, The doc of RequireJS http://requirejs.org/docs/api.html - Section 1.2.7 - Console Debugging points out that the code *require('shCore').SyntaxHighlighter * works only if module definition of *shCore* has been loaded into browser. Assume that shCore.js follows module pattern<http://www.adequatelygood.com/2010/3/JavaScript-Module-Pattern... and the *absolute* URL of shCore.js is shCore_URL, then there are at least 2 ways to make your code work. 1. Define a module named 'shCore' to use it later * define( 'shCore', ['shCore_URL'], function(intermediate_var) { return intermediate_var; }); require('shCore').SyntaxHightlighter; * 2. Put all business code with shCore in a callback * require( [ "shCore_URL"] , function(shCore) { var sh = shCore.SyntaxHightlighter; //Business code with SyntaxHighlighter }); *