function getUrlParameter(parameterName) {
  	parameterName = parameterName.replace(/[\[]/,"\\\[").replace(/[\]]/,"\\\]");
  	var regexS = "[\\?&]"+parameterName+"=([^&#]*)";
  	var regex = new RegExp( regexS );
  	var results = regex.exec( window.location.href );
  	if( results == null )
    		return null;
  	else
    		return results[1];
}