<script type="text/javascript" src="jquery-3.2.1.js"></script>
<script type="text/javascript">
 function OnInput (event) {
 alert (event.target.value);
 }
 function OnPropChanged (event) {
 if (event.propertyName.toLowerCase () == "value") {
 alert (event.srcElement.value);
 }
 }
</script>
<form>
 用戶名:<input name="user" type="text" oninput="OnInput (event)" onpropertychange="OnPropChanged (event)"/>
</form>