Passing parameters in Javascript onClick event

Question

I'm trying to pass a parameter in the onclick event. Below is a sample code:

<div id="div"></div>

<script language="javascript" type="text/javascript">
   var div = document.getElementById('div');

   for (var i = 0; i < 10; i++) {
       var link = document.createElement('a');
       link.setAttribute('href', '#');
       link.innerHTML = i + '';
       link.onclick=  function() { onClickLink(i+'');};
       div.appendChild(link);
       div.appendChild(document.createElement('BR'));
       }

   function onClickLink(text) {
       alert('Link ' + text + ' clicked');
       return false;
       }
    </script>

However whenever I click on any of the links the alert always shows 'Link 10 clicked'!

Can anyone tell me what I'm doing wrong?

Thanks

Answer 1

This is happening because they're all referencing the same i variable, which is changing every loop, and left as 10 at the end of the loop. You can resolve it using a closure like this:

link.onclick = function(j) { return function() { onClickLink(j+''); }; }(i);

You can give it a try here

Or, make this be the link you clicked in that handler, like this:

link.onclick = function(j) { return function() { onClickLink.call(this, j); }; }(i);

You can try that version here

Answer 2

or you could use this line:

 link.setAttribute('onClick', 'onClickLink('+i+')');

instead of this one:

link.onclick=  function() { onClickLink(i+'');};