IE9以上的 输入框监控字数

<input id="ipt" type="text" />
<script type="text/javascript">
    function addEvent(el,type,fn){
        if(el.addEventListener){
            el.addEventListener(type, fn, false);
        }else{
            el.attachEvent(‘on‘ + type, fn);
        }      
    }
    var ipt = document.getElementById(‘ipt‘);
    addEvent(ipt,‘textInput‘,function(e){
        e = e || window.event;
        console.log(e.data);
    });
</script>