var extractParam=function(param){url_params=document.location.search;if(url_params.indexOf(param)<0)
return"";var start_idx=url_params.indexOf(param+"=")+(param.length+1);var end_idx=url_params.indexOf("&",start_idx);var value="";if(end_idx>=0)
value=decodeURIComponent(url_params.substring(start_idx,end_idx));else
value=decodeURIComponent(url_params.substring(start_idx));return value;}