Div Full Width / Height of viewport

// global vars
var winWidth = $(window).width();
var winHeight = $(window).height();

// set initial div height / width
$
('div').css({
'width': winWidth,
'height': winHeight,
});

// make sure div stays full width/height on resize
$
(window).resize(function(){
$
('div').css({
'width': winWidth,
'height': winHeight,
});
});