var checkRegisterForm = function () {
    // TODO:
    var
        reUserName = /\w{3,10}/,
        strUserName = document.getElementById('username').value,
        rePwd1 = /.{6,20}/,
        strPwd1 = document.getElementById('password').value,
        strPwd2 = document.getElementById('password-2').value;
    if(reUserName.test(strUserName)){
        if(rePwd1.test(strPwd1)){
            if(strPwd1 === strPwd2){
                alert("注册成功!");
                return true;
            } else {
                alert("两次口令必须一致!");
                return false;
            }
        } else {
            alert("口令必须是6到20位");
            return false;
        }
    } else {
        alert("用户名必须是3到10位的数字或字母");
        return false;
    }
}