How to add parameters to a URL that already contains other parameters and maybe an anchor

Question

I\'m wondering how I can add a new parameter to an existing url. The problem is: the url may also contain an anchor.

For example:

http://www.example         


        

Answer 1

This can be another good solution, this version is even able to replace the parameter if it already exists, add parameter without value:

function addParam(url, param, value) {
   var a = document.createElement('a'), regex = /(?:\?|&|&)+([^=]+)(?:=([^&]*))*/g;
   var match, str = []; a.href = url; param = encodeURIComponent(param);
   while (match = regex.exec(a.search))
       if (param != match[1]) str.push(match[1]+(match[2]?"="+match[2]:""));
   str.push(param+(value?"="+ encodeURIComponent(value):""));
   a.search = str.join("&");
   return a.href;
}

url = "http://www.example.com#hashme";
newurl = addParam(url, "ciao", "1");
alert(newurl);

http://jsfiddle.net/bknE4/81/