以下是一段JavsScript脚本，但运行时总会产生 “Microsoft JScript 运行时错误: 'null' 为空或不是对象”异常，大家帮看一下。
<form id="form1" runat="server">
<asp:TextBox ID="TextBox1" runat="server" Text =""></asp:TextBox>
<script id="scr1" type ="text/javascript" >
function getValue() {
var x = document.getElementById("Text1");
alert (x.getAttribute("Text"))
}
</script>
<input id="Button1" type="button" value="button" onclick ="getValue()"
<asp:TextBox ID="TextBox1" runat="server" Text =""> </asp:TextBox>
<script id="scr1" type ="text/javascript" >
function getValue() {
var x = document.getElementById("<%= TextBox1.ClientID %>");
alert (x.getAttribute("value"))
}
</script>
<input id="Button1" type="button" value="button" onclick ="getValue()"
document.getElementById("TextBox1");
或document.getEl
