1、css_hack
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
#test{
width: 200px;
height: 200px;
background: pink\9\0;
}
</style>
</head>
<body>
<div id="test">
</div>
</body>
</html>
参考：
https://blog.csdn.net/freshlover/article/details/12132801
http://www.cnblogs.com/sharpxiajun/p/3292498.html
https://baike.baidu.com/item/css%20hack
2、检测低版本IE浏览器
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>自定义检测低版本ie的函数</title>
</head>
<body>
</body>
<script type="text/javascript">
console.log(isIE(8));
//js中的作用域都是函数作用域
function isIE(version){
var b = document.createElement("b");
b.innerHTML="<!--[if IE "+version+"]><i></i><![endif]-->";
return b.getElementsByTagName("i").length == 1 ;
}
//伪数组: 具有length属性的js对象
// console.log(document.body.getElementsByTagName("i").length);
</script>
</html>
3、js变量左右查询
左查询不到进行变量提示
右查询不到抛出异常
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
</head>
<body>
</body>
<script type="text/javascript">
//左查询 对等号左侧的变量进行查询
test()
function test() {
var a = 8;
b = a;
console.log(b); //8
}
//右查询 等号的非左侧
console.log(b); //8
</script>
</html>参考：
https://juejin.im/entry/5acb0dc55188255c5668bbe2?utm_source=gold_browser_extension