Question

post.php?replyto=username&othervariable=value

For example, if I click a link with this url, then I want to take the replyto=username value and insert the value in a textbox using jquery.

function insertParamIntoField(url, param, field) { 
       var anchor = document.createElement('a'), query;
       anchor.value = url;
       query = anchor.query.split('&');

       for(var i = 0, kv; i < query.length; i++) {
          kv = query[i].split('=', 2);
          if (kv[0] == param) {
             field.value = kv[1];
             return;
          }
       }  
    }

    $("a .reply").click(function () {
       insertParamIntoField(this.href, "replyto", $("input .inputField")[0]);
       return false; // prevent default action
    });

this is my html code:

<textarea name="inputField" id="inputField" tabindex="1" rows="2" cols="40"></textarea>
<a class ="reply"  href="home.php?replyto=username">reply</a>

Answer 1

function insertParamIntoField(url, param, field) { 
   var anchor = document.createElement('a'), query;
   anchor.href = url;
   query = anchor.search.substring(1, anchor.search.length).split('&');

   for(var i = 0, kv; i < query.length; i++) {
      kv = query[i].split('=', 2); console.log(kv);
      if (kv[0] == param) {
         field.value = kv[1];
         return;
      }
   }  
}

$("a.reply").click(function () {
   insertParamIntoField(this.href, "replyto", $("textarea.inputField")[0]);
   return false; // prevent default action
});

The insertParamIntoField function will work for any well formed URL (as a string). It works by creating a new anchor DOMElement (but never attaches it to the dom) for that URL and then by using the built in properties of anchor elements (query, hash, etc.) to extract what we want.

If the URL is from an anchor element, we can create a new version of this function that uses that existing anchor rather than creating a new one:

function insertParamIntoField(anchor, param, field) { 
   var query = anchor.search.substring(1, anchor.search.length).split('&'); // anchor is a DOMElement 

   for(var i = 0, kv; i < query.length; i++) {
      kv = query[i].split('=', 2);
      if (kv[0] == param) {
         field.value = kv[1];
         return;
      }
   }  
}

$("a.reply").click(function () {
   insertParamIntoField(this, "replyto", $("textarea.inputField")[0]);
   return false; // prevent default action
});