【opacity】
<!DOCTYPE html>
<html>
<head>
<script type='text/javascript'
src='http://code.jquery.com/jquery-1.9.1.js'></script>
<style type='text/css'>
#menu div {
opacity: 0.7;
}
</style>
<script type='text/javascript'>
$(window).load(function(){
$("#menu DIV").hover(
function () {
$(this).css({ opacity: 1 });
console.log($(this));
},
function () {
$(this).css({ opacity: 0.4 });
}
);
});
</script>
</head>
<body>
<div id="menu">
<div>Testing...</div>
</div>
</body>
</html>
