我这里是可以的啊:
<body MS_POSITIONING="GridLayout">
<script language=javascript>
function a()
{
var obj=document.getElementById('TextBox1');
obj.style.display='inline';
}
function b()
{
var obj=document.getElementById('TextBox1');
obj.style.display='none';
}
</script>
<form id="Form1" method="post" runat="server">
<asp:TextBox onmouseout=b() id="TextBox1" style="Z-INDEX: 101; LEFT: 128px; POSITION: absolute; TOP: 40px" runat="server" Width="152px"></asp:TextBox>
<INPUT onclick=a() style="Z-INDEX: 102; LEFT: 160px; WIDTH: 72px; POSITION: absolute; TOP: 144px; HEIGHT: 24px" type="button" value="Button">
</form>
</body>