// JavaScript Document
var topdiv = "topdiv"; //ID de la DIV relative
var bottom = "imgBottom";
var htinit = 0;
var htinit2 = 0;
window.onload = function() { 
	htinit = document.getElementById(topdiv).offsetTop;
	htinit2 = document.getElementById(bottom).offsetTop;
	alert("1er div= "+htinit+" / 2e div= "+htinit2);
}