加上alert（）调试就没问题
去掉alert（），就会有问题


function checkgender(){
    //性别验证
        var gender = document.getElementById("gender").value;
        alert（gender）;
        var reltypesecond = document.getElementById("reltypesecond").value;
        alert(reltypesecond);

        if ((((reltypesecond == '0101') || (reltypesecond == '0201') || (reltypesecond
== '0202') || (reltypesecond == '0203') || (reltypesecond == '0204') ||
(reltypesecond == '0304') || (reltypesecond == '0401')) && gender == '2')
|| (((reltypesecond == '0102') || (reltypesecond == '0205') || (reltypesecond
== '0206') || (reltypesecond == '0207') || (reltypesecond == '0208') ||
(reltypesecond == '0303') || (reltypesecond == '0402'))  && gender == '1'
)){
                alert("关系人类型与性别不符！");
                document.forms[0].gender.value = '0';
                document.forms[0].reltypesecond.value = '';
                return false;
        }
}
--
FROM 123.118.8.*