javascript不能返回true

Question

我无法让javascript函数验证是否返回true ...有人知道为什么吗？我的目标是添加JavaScript来验证表单，以便在输入框下显示错误。我已经实现了这一部分，我只是无法获得validate函数以返回true来提交表单。我的印象是我需要验证以返回正确的方式，因为我已经以HTML形式定义了功能

In the HTML the form is as such <form action ='reg.php' method ='POST' onsubmit='return function();'>
//markup 
</form>


 var form = document.getElementById('registration');
    var errorDisplay = document.getElementById('nameError');
    var errorEmail = document.getElementById('emailError');
    var errorPassword = document.getElementById('passwordError');
    var errorConfirmPassword = document.getElementById('passwordConfirmError');

    var validateNameField = document.getElementById('FullNameField');
    var validateEmailField = document.getElementById('emailField');
    var validatePasswordField = document.getElementById('passwordField');
    var validateConfirmPasswordField = document.getElementById('confirmPasswordField');

    validateNameField.addEventListener('blur',checkName,true);
    validateEmailField.addEventListener('blur',checkEmail,true);
    validatePasswordField.addEventListener('blur',checkPassword,true);
    validateConfirmPasswordField.addEventListener('blur',checkConfirmPassword,true);



    function checkName(){
      if(validateNameField.value !=''){
        errorDisplay.innerHTML='';
        return true;
      }
    }

    function checkEmail(){
      var emailRegEx =/\S+@\S+\.\S+/;
      if(emailRegEx.test(validateEmailField.value)){
        errorEmail.innerHTML='';
        return true;
      }
    }
    function checkPassword(){
      if(validatePasswordField.value !=''){
        errorPassword.innerHTML='';
        return true;
      }
    }
    function checkConfirmPassword(){
      if(validateConfirmPasswordField.value !=''){
        errorConfirmPassword.innerHTML='';
        return true;
      }
    }

    function validate(){

    var formFields = document.getElementsByTagName('input');
    var emailRegEx =/\S+@\S+\.\S+/;


        if(formFields[0].name = 'FullName' && !(formFields[0].value)){
            errorDisplay.innerHTML='name is required';
            return false;
        }

        if (formFields[1].name = 'email' && !emailRegEx.test(formFields[1].value)){
            errorEmail.innerHTML='valid email required';
            return false;
        }

        if (formFields[2].name = 'password' && !(formFields[2].value)){
            errorPassword.innerHTML='password is required';
            return false;
        }

        if (formFields[3].name = 'password_confirmed' && !(formFields[3].value)){
            errorConfirmPassword.innerHTML='confirm password is required';
            return false;
        }

        if(formFields[2].value !== formFields[3].value){
              errorConfirmPassword.innerHTML='passwrod does not mathch comfirm';
              return false;
        }
    return true;
    }