jq input 事件? 原理是什么？？

Question

jquery 的 input 事件可以实时获取 input 框的值，这是什么js 原理？

<input name="a" id="a" value="1">

<script>

    $("#a").on("input",function(){})

<script>

Answer 1

js的oninput事件,ie9以下是onpropertychange 事件oninput 事件在用户输入时触发。var oinp = document.getElementById('a');&nbsp;oninput(oinp,function(){});function oninput(obj,fn){&nbsp; &nbsp; var ie = !!window.ActiveXObject;&nbsp;&nbsp;&nbsp; &nbsp; if(ie){&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; obj.onpropertychange = fn;&nbsp;&nbsp;&nbsp; &nbsp; }else{&nbsp;&nbsp;&nbsp; &nbsp; &nbsp; &nbsp; obj.addEventListener("input",fn,false);&nbsp;&nbsp;&nbsp; &nbsp; }&nbsp;}&nbsp;