<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
</head>
<body>
<div id="box2" class="box1"></div>
<script>
window.onload = function (ev) {
//1.利用原生的js查找dom元素
var div1 = document.getElementsByTagName("div")[0];//根据div标签名--获取第0个<div>
var div2 = document.getElementsByClassName("box1")[0];//根据class类名获取
var div3 = document.getElementById("box2");//根据id获取
//2.利用原生js修改背景颜色
div1.style.backgroundColor = "red";
div2.style.backgroundColor = "blue";
div3.style.backgroundColor = "yellow";
}
//利用jquery获取
$(function () {
var $div1 = $("div")[0];
var $div2 = $(".box1")[0];
var $div3 = $("#box2")[0];
$div1.css({
background:"red",
width:"200px"
});
})
</script>
</body>
</html>
