<img id="imgAtt" src="nullImg.gif" border="0" runat="server" style="height:250px; 300px;" /></br><asp:RegularExpressionValidator ID="RegularExpressionValidator1" runat="server" ControlToValidate="File1" ValidationGroup="ValAtt"
ErrorMessage="只能上传图片格式" ValidationExpression="^.*?\.(jpg|jpeg|bmp|gif|JPG|GIF|png|PNG|BMP|ico|)$"
></asp:RegularExpressionValidator></br>
<input type="file" id="File1" name="File1" runat="server"
style="border: 1px solid #333333; background-color: #999999;
280px" onchange="ChangeImg()" />
<script type="text/javascript">
function ChangeImg() {
var obj = document.getElementById("<%= imgAtt.ClientID %>");
var img = document.getElementById("<%=File1.ClientID %>");
var tmp = img.value.substr(0, img.value.indexOf(":") + 1);
var url = img.value.replace(tmp, "file://");
obj.src = url;
}
</script>