为什么每当我提交表单时,都会要求选择男性/女性,而表单却没有提交

function validation()
{
var uid = document.registration.userid;
var passid = document.registration.passid;
var uname = document.registration.name;
var uadd = document.registration.address;
var ucountry = document.registration.country;
var uzip = document.registration.zip;
var uemail = document.registration.email;
var umsex = document.registration.sex;
var ufsex = document.registration.sex;

if(userid_validation(uid,5,12))
{
if(passid_validation(passid,7,12))
{
if(allLetter(uname))
{
if(alphanumeric(uadd))
{ 
if(countryselect(ucountry))
{
if(allnumeric(uzip))
{
if(ValidateEmail(uemail))
{
if(validsex(umsex,ufsex))
{
}
} 
}
} 
}
}
}
}
return false;
}

function userid_validation(uid,mx,my)
{
var uid_len = uid.value.length;
if (uid_len == 0 || uid_len >= my || uid_len < mx)
{
alert("User Id should not be empty or length should be between "+mx+" to "+my);
uid.focus();
return false;
}
return true;
}


function passid_validation(passid,mx,my)
{
var passid_len = passid.value.length;
if (passid_len == 0 ||passid_len >= my || passid_len < mx)
{
alert("Password should not be empty or length should be between "+mx+" to "+my);
passid.focus();
return false;
}
return true;
}

function allLetter(uname)
{ 
var letters = /^[A-Za-z ]+$/;
if(uname.value.match(letters))
{
return true;
}
else
{
alert('Name must have alphabet characters only');
uname.focus();
return false;
}
}

function alphanumeric(uadd)
{ 
var letters = /^[0-9a-zA-Z]+$/;
if(uadd.value.match(letters))
{
return true;
}
else
{
alert('User address must have alphanumeric characters only');
uadd.focus();
return false;
}
}

function countryselect(ucountry)
{
if(ucountry.value == "Default")
{
alert('Select your country from the list');
ucountry.focus();
return false;
}
else
{
return true;
}
}

function allnumeric(uzip)
{ 
var numbers = /^[0-9]+$/;
if(uzip.value.match(numbers))
{
return true;
}
else
{
alert('ZIP code must have numeric characters only');
uzip.focus();
return false;
}
}


function ValidateEmail(uemail)
{
var mailformat = /^\w+([\.-]?\w+)*@\w+([\.-]?\w+)*(\.\w{2,3})+$/;
if(uemail.value.match(mailformat))
{
return true;
}
else
{
alert("You have entered an invalid email address!");
uemail.focus();
return false;
}
}


function validsex(umsex,ufsex)
{
x=0;

if(umsex.checked) 
{
x++;
} if(ufsex.checked)
{
x++; 
}
if(x==0)
{
alert('Select Male/Female');
umsex.focus();
return false;
}
else
{
alert('Form Successfully Submitted');
window.location.reload()
return true;}
}
h1 {
margin-left: 400px;
}
form li {
list-style: none;
}

form {
    margin-left: 320px;
}

form ul li label{
float: left;
clear: left;
width: 100px;
text-align: right;
margin-right: 10px;
font-size: 18px;
font-weight: bold;

}

form ul li input, select, span {
float: left;
margin-bottom: 10px;
}

form textarea {
float: left;
width: 350px;
height: 200px;
}

[type="submit"] {
clear: left;
margin-left: 255px;
margin-top: 20px;
font-size:18px
}

p {
margin-left: 70px;
font-weight: bold;
}
<!DOCTYPE html>
<html>
<head>

<title> Exercise 4 (Registration Page) </title>
<link rel="stylesheet" href="E4.css">
<script src="E4.js"></script>
</head>
<h1>Registration Form</h1>
<form name='registration' onSubmit="return validation();">
<ul>
<li><label for="userid">User id:</label></li>
<li><input type="text" name="userid" size="12" /></li>

<li><label for="passid">Password:</label></li>
<li><input type="password" name="passid" size="12" /></li>

<li><label for="name">Name:</label></li>
<li><input type="text" name="name" size="50" /></li>

<li><label for="address">Address:</label></li>
<li><input type="text" name="address" size="50" /></li>

<li><label for="country">Country:</label></li>
<li><select name="country">

<option selected="" value="Default">(Please select a country)</option>
<option>Australia</option>
<option>Afghanistan</option>
<option>Brazil</option>
<option>China</option>
<option>Canada</option>
<option>Denmark</option>
<option>Egypt</option>
<option>France</option>
<option>Germany</option>
<option>India</option>
<option>Japan</option>
<option>Korea</option>
<option>Madagascar</option>
<option>Malaysia</option> 
<option>Nepal</option>
<option>New Zealand</option>
<option>Nigeria</option>
<option>Philippines</option>
<option>Qatar</option>
<option>Russia</option>
<option>Saudi Arabia</option>
<option>Serbia</option>
<option>Singapore</option>
<option>South Africa</option>
<option>Spain</option>
<option>Turkey</option>
<option>USA</option>
<option>Yemen</option>
<option>Zimbabwe</option>

</select></li>


<li><label for="zip">ZIP Code:</label></li>
<li><input type="text" name="zip" /></li>

<li><label for="email">Email:</label></li>
<li><input type="text" name="email" size="50" /></li>

<li><label id="gender">Sex:</label></li>
<li><input type="radio" name="sex" value="Male" /><span>Male</span></li>
<li><input type="radio" name="sex" value="Female" /><span>Female</span></li>

<li><label>Language:</label></li>
<li><input type="checkbox" name="en" value="en" checked /><span>English</span></li>
<li><input type="checkbox" name="nonen" value="noen" /><span>Non English</span></li>

<li><label for="desc">About:</label></li>
<li><textarea name="desc" id="desc"></textarea></li>

<li><input type="submit" name="submit" value="Submit" /></li>

</ul>
</form>

<body>
</body>
</html>

当我单击“提交”按钮完全填写表格后,它会显示单选按钮验证,该验证已选择“男性”或“女性”,但先前已选择该选项,并且单击了警报中的“确定” 我输入的所有数据都会被删除,请帮忙。

我已将.js .css和.html文件插入了性别部分,请在最后一节中进行一次检查。我没有弄错什么。