Question

为什么老是说JS缺少对象，总是提示错误呢

<tr>
<td colspan="2">
会员密码：<asp:TextBox ID="I_pwd" runat="server" TextMode="Password"></asp:TextBox>
</td>
<script language="javascript">
function check(){
if(document.this.I_pwd.Text != document.this.ppwd.Text)
alert("密码不一致，请重输");
this.I_pwd.Text="";
this.I_pwd.focus();
}
</script>
<td colspan="2">
确认密码：<asp:TextBox ID="ppwd" runat="server" TextMode="Password" onblur="check()" ></asp:TextBox>
</td>
</tr>
<script language="javascript">

function check(){
if( document.getElementById("I_pwd").value != document.getElementById("ppwd").value)
alert("密码不一致，请重输!");
}

</script>
if( document.getElementById("I_pwd").value != document.getElementById("ppwd").value)
到底错哪里啊！

Answer 1

//if(document.this.I_pwd.Text != document.this.ppwd.Text)等有问题

function check(){
var I_pwd=document.getElementById("I_pwd");
if( I_pwd .value!=document.getElementById("ppwd") .value) {
alert("密码不一致，请重输");
I_pwd.value="";
I_pwd.focus();}
}

IF少掉大括号{}

Answer 2

onblur="check()" 换成 onblur="check(this)"
<script language="javascript">
function check(obj){
if (obj.value != document.getElementById('I_pwd').value) {
alert("密码不一致，请重输");
document.getElementById('I_pwd').value="";
document.getElementById('I_pwd').focus();
}
</script>

Answer 3

我的回答会失效，不能回答。
楼上正解。