49.习题:
一小时45分例题上面也有例题
习题1:
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>frame</title>
<style type = "text/css">
*{
margin : 0;
padding : 0;
}
ul{
list-style: none;
}
li:nth-of-type(2n){
background-color:pink;
}
li:nth-of-type(2n + 1){
background-color:palegreen;
}
</style>
</head>
<body>
<ul>
<li>a</li>
<li>a</li>
<li>a</li>
<li>a</li>
</ul>
<script type = "text/javascript">
var liCollection = document.getElementsByTagName('li');//将所有li放进数组liCollection里
for(var i = 0; i < liCollection.length; i ++){
(function(j){ //利用立即执行函数使每个属性索引值不同也就是解决闭包问题
liCollection[j].onclick = function(){ //为每一个li赋予属性
console.log(j);
}
}(i))
}
</script>
</body>
</html>