1
<input><span id=demo></span>
<br>123
<script>demo.innerText="Error"</script>2.
<input id=demo2>
<br>123
<script>demo2.insertAdjacentText("afterEnd","Error")</script>
<input><span id=demo></span>
<br>123
<script>demo.innerText="Error"</script>2.
<input id=demo2>
<br>123
<script>demo2.insertAdjacentText("afterEnd","Error")</script>
<INPUT TYPE="text" NAME="bb" value="bb" onchange="chkthis(this)"><BR>
<SCRIPT LANGUAGE="JavaScript">
<!--
function chkthis(v){
if (v.value == "") {
var myNewNode = document.createTextNode("请输入信息");
document.body.insertBefore(myNewNode,v.nextSibling);
}
}
//-->
</SCRIPT>