<form id="myForm" name="myForm">
    <label for="user">UserName
        <input type="text" id="user" name="user">
    </label>
    <label for="psw">Password
        <input type="password" id="password">
    </label>
    <label for="gender" id="gender">
        Male<input type="Radio" Name="Gender" Value="Male" id="male">
        Female<input type="Radio" Name="Gender" Value="Female" id="female">
    </label>
    <label for="selMALE">Прически у мужчин
        <select name="selMALE" id="selMALE" disabled>
            <option value="Британка">Британка</option>
            <option value="Бокс">Бокс</option>
            <option value="Полубокс">Полубокс</option>
        </select>
    </label>
    <label for="selFEMALE" >Прически у женщин
        <select name="selFEMALE" id="selFEMALE" disabled>
            <option value="Пикси">Пикси</option>
            <option value="Ассиметричная">Ассиметричная</option>
            <option value="Шапочка">Шапочка</option>
        </select>
    </label>

    <a href="javascript:submit()"><button type="button">Submit</button></a>
</form>

<div class="show">
    <h3 id="userShow">Username :</h3>
    <h3 id="passShow">Password :</h3>
    <h3 id="genShow">Gender :</h3>
    <h3 id="hairShow">Hair style :</h3>
</div>

var f = document.getElementById("myForm");
var gender = document.getElementById("gender");

gender.onclick =  function(){
    var radio = f.Gender.value;
    if (radio == "Male") {
        f.selMALE.disabled = false;
        f.selFEMALE.disabled = true;
        document.getElementById("genShow").innerHTML = "Gender " + ": " + f.male.value;
    document.getElementById("hairShow").innerHTML = "HairStyle " + ": " + f.selMALE.value;
} else if(radio == "Female"){
    f.selFEMALE.disabled = false;
    f.selMALE.disabled = true;
    document.getElementById("genShow").innerHTML = "Gender " + ": " + f.female.value;
    document.getElementById("hairShow").innerHTML = "HairStyle " + ": " + f.selMALE.value;
    }
};

function submit() {
    var user = document.getElementById("user").value;
    var pass = document.getElementById("password").value;
    if (user.length > 3 && user.length <= 10) {
        document.getElementById("userShow").innerHTML = "Username " + ": " +     user;
    } else {
        document.getElementById("userShow").innerHTML = "Мин количество значений 4, Макс 10";
    }

    if (pass.match(/^d+$/)) {
        document.getElementById("passShow").innerHTML = "Password" + ": " + pass;
    } else{
        document.getElementById("passShow").innerHTML = "Введите только цифры";
    }
}