jQuery script only working under ie8/9 developer tools-Collection of common programming errors

The error is (in slider.js):

'console' is undefined

The console object is only defined in IE when you open the Developer Tools. Then, there’s no longer a JavaScript error and everything works.

To fix the problem, you can either remove/comment out the console.log call, or add something like this as your very first block of JavaScript:

// make it safe to use console.log always
(function(b){function c(){}for(var d="assert,count,debug,dir,dirxml,error,exception,group,groupCollapsed,groupEnd,info, log,markTimeline,profile,profileEnd,time,timeEnd,trace,warn".split(","),a;a=d.pop();)b[a]=b[a]||c})(window.console=window.console||{});

(snippet taken from http://html5boilerplate.com/)