Not Working in IE11

[coldes]

...fyi, does not work in IE11*, both demo site and a dev site I have set up - main issue is Cart View will not close, and in demo site, detail view after close, container contents remain empty!

...also fyi, from other "finding solutions" for simpleCartJS issues [which are sooooo many), came across this site using simpleCartJS, http://www.carpalwatch.com/shop/ AND this person has a site that appears to work 100%

*yes I know, why FFS are people still using ie11?
... plus, if interested, a small script error fix for ie11 in simpleStore.js

var msg,   // ref is undefined my add
refLength; 

//if (msg.length) {
if(msg) {
	refLength = msg.length;
	$tmpl.find('.error_text').text(msg);
} 
else {
	refLength = 0;
}