<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
.wrap{
width: 200px;
height: 200px;
border: 1px solid deepskyblue;
background-color: blanchedalmond;
position: relative;
top: 20px;
left: 20px;
}
#div1{
width: 100px;
height: 100px;
background-color: violet;
border: 1px solid #00FF7F;
position: absolute;
}
</style>
<script src="js/jquery-2.1.3.min.js" type="text/javascript" charset="utf-8"></script>
<script type="text/javascript">
// 原生js写法 offsetTop相对于父级的top值
// window.onload = function(){
// var div1 = document.getElementById("div1");
// console.log(div1.offsetTop); // 相对于父级
// }
// jq下offset().top是相对于文档的位置值
$(document).ready(function(){
console.log($("#div1").offset().top);
})
</script>
</head>
<body>
<div class="wrap">
<div id="div1">
</div>
</div>
</body>
</html>