js的一个有意思的小题，闭包解决getElementByTagName的for循环绑定事件错误问题

<a href="javaScript:void(0)">a</a>
<a href="javaScript:void(0)">b</a>
<a href="javaScript:void(0)">c</a>

<script type='text/javascript'>
var arr = document.getElementsByTagName('a');
for(var i=0;i<arr.length;i++) {
arr[i].onclick = function() {
console.log(this + '我是第'+ i +'几个');
}
}
</script>

<a href="javaScript:void(0)">a</a>
<a href="javaScript:void(0)">b</a>
<a href="javaScript:void(0)">c</a>

<script type='text/javascript'>

var arr = document.getElementsByTagName('a');
for(var i=0;i<arr.length;i++) {
(function(i,v){
v.onclick = function() {
console.log(this + '我是第'+ i +'个');
}
})(i,arr[i])
}
</script>