当我运行提交时，表单不会停止

Question

我有一个.tpl文件，其中包含一个连接到js文件的表单，如果该表单是下面的表单之一，则该文件可以阻止页面执行任何操作：

• 未正确填写
• 不正确的电子邮件fomate或匹配的formate
• 如果没有名字或姓氏

但它似乎跳过所有内容并只运行注册页面

这是我的js代码

function registervalidation() {

    var emailone = document.getElementById("emailone").value;
    var emailtwo = document.getElementById("checkemail").value;
    var firstname = document.getElementById("firstname").value;
    var lastname = document.getElementById("lastname").value;

    if(firstname == null || firstname == "")
    {
        document.getElementById("firstname").classList.add("warning");
     return false;
    }


    if(lastname == null || lastname == "")
    {
        document.getElementById("lastname").classList.add("warning");
     return false;
    }



    if (emailtwo == null || emailtwo == "" ) {
        document.getElementById("emailtwo").classList.add("warning");
        return false;
    }
    if(emailone !== emailtwo)
    {
        document.getElementById("emailtwo").classList.add("warning");
        return false;
    }

    if(validateEmail(document.getElementById('emailone').value)){
    }else{document.getElementById("emailone").classList.add("warning"); return false;}
    if(validateEmail(document.getElementById('emailtwo').value)){
    }else{document.getElementById("emailtwo").classList.add("warning"); return false;}

}

和我的表格

 <script src="//<?=siteurl;?>/template/main/js/registervalidation.js"></script>
        <div class="Grid-cell u-size35of4">
            <div class="internal">
                <h1 class="hevetics">Sign up</h1>
                <p class="signuptext">It's free and always will be.</p>
                <form action="/signup" name="register" method="post" class="ipetsignup" enctype="multipart/form-data"  onsubmit="return registervalidation();">
                    <label>
                        <span><input id="firstname" type="text" name="firstname" placeholder="First Name" class="half" onchange="name();"/></span><input id="lastname" id="name" type="text" name="lastname" onchange="name();" placeholder="Last Name" class="half right" />
                    </label>

                    <label>
                        <input id="emailone" type="email" name="email" placeholder="Your Email" onchange="checkemails();" />


                    </label>
                    <label>
                        <input id="emailtwo" type="email" name="checkemail" placeholder="re-enter Email"  onchange="checkemailtwo();" />
                    </label>
                    <label>
                        <input id="password" type="password" name="password" placeholder="New Password" />
                    </label>

                    <label>
                         <input id="signup" type="submit" class="button" value="Sign up" /> 
                    </label>    
                </form>
            </div>    
        </div>