// JavaScript Document
function GetHeight()
{
        var y = 0;
        if (self.innerHeight)
        {
                y = self.innerHeight;
        }
        else if (document.documentElement && document.documentElement.clientHeight)
        {
                y = document.documentElement.clientHeight;
        }
        else if (document.body)
        {
                y = document.body.clientHeight;
        }
        return y;
}

window.onload = function()
        {
            var a = document.getElementById("div1").offsetHeight;
            var b = document.getElementById("div2").offsetHeight;
            var c = document.getElementById("div3").offsetHeight;
            
            var ht = a>b?a:b;
            ht = ht>c?ht:c;
            ht1 = GetHeight();
            
            //ht = (ht>ht1)?ht:ht1;
            document.getElementById("div1").style.height = ht;
            document.getElementById("div2").style.height = ht;
            document.getElementById("div3").style.height = ht;
        }