<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html>
<head>
<title>js</title>
<script src="http://code.jquery.com/jquery-latest.js" type="text/javascript"></script>
<script type="text/javascript">
$(document).ready(function () {
$(window).scroll(function () {
var a = document.getElementById("eq").offsetTop;
if (a >= $(window).scrollTop() && a < ($(window).scrollTop()+$(window).height())) {
alert("div在可视范围");
}
});
});
</script>
</head>
<body>
<div style="1px;height:2000px;"></div>
<div id="eq" style=" 100px; height:100px; background-color:Red;">1</div>
<div style="1px;height:2000px;"></div>
</body>
</html>