/* 检查注册 */
function CheckReg() {
    var textfield = $("#textfield").val();

    if (isNull(textfield)) {
        alert("邮箱不能为空，请您输入正确的邮箱地址!");
        $("#textfield").focus();
        return false;
    }
    else {
        if (!ismail(textfield)) {
            alert("邮箱格式不正确，请您输入正确的邮箱地址!");
            $("#textfield").focus();
            return false;
        }
    }

    var url = "http://help.160.com/CheckEmail.aspx?email=" + escape(textfield);
    var sform = document.createElement("form");
    sform.action = url;
    sform.method = "post";
    sform.target = "_blank";
    document.body.appendChild(sform);
    sform.submit();
    
}