var addEvent = document.addEventListener?
function( node, type, handler ){ node.addEventListener( type, handler, false ); }:
function( node, type, handler ){ node.attachEvent( 'on' + type, function( evt ){ handler.call( node, evt );});};

addEvent( window, "load", function(){
var b = document.body;

var op = 0, add = 0.05, ms = 50;
var timerID = setInterval( function(){
op += add;
if( op > 1.0 ){ clearInterval( timerID ); }
else{
b.style.opacity = op;
b.style.filter = 'alpha( opacity=' + ( op*100 ) + ')';
}
}, ms);
});