VueJS template - Flip between Login Form & Register Form

Issue

I am trying to Flip between 'Login Form' & 'Register Form'. I tried to use code which I came across on codepen Flat HTML5/CSS3 Login Form. The code works just fine, but when I integrate the HTML code within a Vue Template the Form does not flip to the 'Create an account' form. I have observed that there is something to correct in the JavaScript but I am not able to understand exactly what.

My code is as below:

HTML

<template id="login-page"> // PROBLEM When this Tag is added and called using VueJS component
<div class="login-page">
  <div class="form">
    <form class="register-form">
      <input type="text" placeholder="name"/>
      <input type="password" placeholder="password"/>
      <input type="text" placeholder="email address"/>
      <button>create</button>
      <p class="message">Already registered? <a href="#">Sign In</a></p>
    </form>
    <form class="login-form">
      <input type="text" placeholder="username"/>
      <input type="password" placeholder="password"/>
      <button>login</button>
      <p class="message">Not registered? <a href="#">Create an account</a></p>
    </form>
  </div>
</div>
</template>  // PROBLEM When this Tag is added and called using VueJS component

VueJS

// Vue component: login-page
const LoginPage = {
    template: '#login-page',
    data() {
        return {
            login_message: 'Please enter your credentials to login.',
            loginStage: 'login-form',
            }
        },
    }

JavaScript

<script>
$('.message a').click(function(){
   $('form').animate({height: "toggle", opacity: "toggle"}, "slow");
});
</script>

CSS

<style>
@import url(https://fonts.googleapis.com/css?family=Roboto:300);

.login-page {
  width: 360px;
  padding: 8% 0 0;
  margin: auto;
}
.form {
  position: relative;
  z-index: 1;
  background: #FFFFFF;
  max-width: 360px;
  margin: 0 auto 100px;
  padding: 45px;
  text-align: center;
  box-shadow: 0 0 20px 0 rgba(0, 0, 0, 0.2), 0 5px 5px 0 rgba(0, 0, 0, 0.24);
}
.form input {
  font-family: "Roboto", sans-serif;
  outline: 0;
  background: #f2f2f2;
  width: 100%;
  border: 0;
  margin: 0 0 15px;
  padding: 15px;
  box-sizing: border-box;
  font-size: 14px;
}
.form button {
  font-family: "Roboto", sans-serif;
  text-transform: uppercase;
  outline: 0;
  background: #4CAF50;
  width: 100%;
  border: 0;
  padding: 15px;
  color: #FFFFFF;
  font-size: 14px;
  -webkit-transition: all 0.3 ease;
  transition: all 0.3 ease;
  cursor: pointer;
}
.form button:hover,.form button:active,.form button:focus {
  background: #43A047;
}
.form .message {
  margin: 15px 0 0;
  color: #b3b3b3;
  font-size: 12px;
}
.form .message a {
  color: #4CAF50;
  text-decoration: none;
}
.form .register-form {
  display: none;
}
.container {
  position: relative;
  z-index: 1;
  max-width: 300px;
  margin: 0 auto;
}
.container:before, .container:after {
  content: "";
  display: block;
  clear: both;
}
.container .info {
  margin: 50px auto;
  text-align: center;
}
.container .info h1 {
  margin: 0 0 15px;
  padding: 0;
  font-size: 36px;
  font-weight: 300;
  color: #1a1a1a;
}
.container .info span {
  color: #4d4d4d;
  font-size: 12px;
}
.container .info span a {
  color: #000000;
  text-decoration: none;
}
.container .info span .fa {
  color: #EF3B3A;
}
body {
  background: #76b852; /* fallback for old browsers */
  background: -webkit-linear-gradient(right, #76b852, #8DC26F);
  background: -moz-linear-gradient(right, #76b852, #8DC26F);
  background: -o-linear-gradient(right, #76b852, #8DC26F);
  background: linear-gradient(to left, #76b852, #8DC26F);
  font-family: "Roboto", sans-serif;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;      
}
</style>

Solution

While @Fred has accepted @chr's answer, this is (still) a mis-use of Vue.
(Note this not an attempt to reproduce the working fiddle, but to answer the general question of how to Flip between 'Login Form' & 'Register Form' using a more Vue-oriented approach)

In the Vue way of doing things the switch between the login form and the register form should be done with markup, using Vue conditional rendering rather than calling functions showRegisterForm() and showLoginForm().
toggleForm doesn't require a parameter because the model knows what the value of currentForm is already.

An if and else is the simplest approach, making use of a property in your Vue model, such as currentForm: 'login' that chr introduced in their answer.
The HTML needs only slight changes

<div id="login-page" class="login-page">
  <div class="form">
    <form v-if="currentForm.toLowerCase() === 'register'" class="register-form">
      <input type="text" placeholder="name"/>
      <input type="password" placeholder="password"/>
      <input type="text" placeholder="email address"/>
      <button>create</button>
      <p class="message">Already registered?
          <a href="#" @click.prevent="toggleForm()">Sign In</a></p>
    </form>
    <form v-else class="login-form">
      <input type="text" placeholder="username"/>
      <input type="password" placeholder="password"/>
      <button>login</button>
      <p class="message">Not registered?
          <a href="#" @click.prevent="toggleForm()">Create an account</a></p>
    </form>
  </div>
</div>

A partial look at the model needed for this could be

const model = new Vue({
    data : {
        'currentForm' : 'login',
        ...
    },
    ...
    methods : {
        toggleForm() {
            this.currentForm = this.currentForm === 'login' ? 'register' : 'login';
        }
    },
    ...
});

When the value of currentForm changes Vue will take care of changing which of the forms will display.

Also see the answer to the question VueJS - Swap component on click for a more generalized approach.

Answered By - Stephen P