Get a query param from the current page url

QueryParam.js

/* Get a parameter from the url */
function getVarFromURL(varName){
	    var url = window.location.href;
	    url = url.substring(url.indexOf('?'));
	    var urlLowerCase = url.toLowerCase();
	    varName = varName.toLowerCase();
	    if (urlLowerCase.indexOf(varName + "=") != -1) {
	        var value = url.substring(urlLowerCase.indexOf(varName) + varName.length + 1);
	        if (value.indexOf('&') != -1) {
	            value = value.substring(0, value.indexOf('&'));
	        }
	        return value;
	    }
	    else {
	        return null;
	    }
	}