JS去空格

<script language="javascript" type="text/javascript">
                String.prototype.Trim = function() { return this.replace(/(^\s*)|(\s*$)/g, ""); }
                function CheckData() {
                    var Uname = document.getElementById('<%=txtUname.ClientID %>').value;
                    var Upwd = document.getElementById('<%=txtUpwd.ClientID %>').value;

                    if (Uname.Trim() == "") {
                        alert('用户名不可以为空！');
                        return false;
                    }
                    if (Upwd.Trim() == "") {
                        alert('密码不可以为空！');
                        return false;
                    }
                    return true;
                }
            </script>