I need to call an object method when a div is clicked...

any idea of how to store the javascript object in the html element?

Use a Hash to store the functions, with the keys being the ids. You then use the same id in the div and in the Hash to lookup the required method.

<div id="unique_987">...</div>

var MyHash = {};

MyHash["unique_987"] = function(){
  alert('yay!');
}

Then hook from the on click event. You probably can choose among some variations of this idea. Basically, it's a good idea to keep the HTML elements as pure as possible, see:
http://blackbeltcoder.net/2007/04/10/javascript-performance-notes/

alert, I found a solution that looks like that...

function f(obj,elementID)
{
div1 = ...
var x = document.getElementById(elementID);
x.appendChild(div1);

div1.onmouseover=function(){obj.g();};
}

div1 is an element. the element gets the javascript object by the function.

later in javascript...

<javascript>
var x = new object();
x.f(x);

what do you think of this solution?

Seems like this will be an slow day...