// JavaScript Document

function redimensiona(){
  //parent.document.getElementById('main').style.height = 0;
  parent.document.getElementById('main').style.height = document.body.scrollHeight+"px";	
}

parent.document.getElementById('main').style.height = 0;
redimensiona();

var num = 0;
objInter = setInterval(function() {
    if(num > 5)
    {
        clearInterval(objInter);
        return;
    }
    redimensiona();
    num++;
}, 500);