Click On The Button To Open The Sign Up form

 

Sign Up Form

<form action="action_page.php" style="border:1px solid #ccc">
  <div class="container">
    <h1>Sign Up</h1>
    <p>Please fill in this form to create an account.</p>
    <hr>
    <label for="email"><b>Email</b></label>
    <input type="text" placeholder="Enter Email" name="email" required>
    <label for="psw"><b>Password</b></label>
    <input type="password" placeholder="Enter Password" name="psw" required>
    <label for="psw-repeat"><b>Repeat Password</b></label>
    <input type="password" placeholder="Repeat Password" name="psw-repeat" required>
    <label>
      <input type="checkbox" checked="checked" name="remember" style="margin-bottom:15px"> Remember me
    </label>
    <p>By creating an account you agree to our <a href="#" style="color:dodgerblue">Terms & Privacy</a>.</p>
    <div class="clearfix">
      <button type="button" class="cancelbtn">Cancel</button>
      <button type="submit" class="signupbtn">Sign Up</button>
    </div>
  </div>
</form>

 

* {box-sizing: border-box}
/* Full-width input fields */
  input[type=text], input[type=password] {
  width: 100%;
  padding: 15px;
  margin: 5px 0 22px 0;
  display: inline-block;
  border: none;
  background: #f1f1f1;
}
input[type=text]:focus, input[type=password]:focus {
  background-color: #ddd;
  outline: none;
}
hr {
  border: 1px solid #f1f1f1;
  margin-bottom: 25px;
}
/* Set a style for all buttons */
button {
  background-color: #4CAF50;
  color: white;
  padding: 14px 20px;
  margin: 8px 0;
  border: none;
  cursor: pointer;
  width: 100%;
  opacity: 0.9;
}
button:hover {
  opacity:1;
}
/* Extra styles for the cancel button */
.cancelbtn {
  padding: 14px 20px;
  background-color: #f44336;
}
/* Float cancel and signup buttons and add an equal width */
.cancelbtn, .signupbtn {
  float: left;
  width: 50%;
}
/* Add padding to container elements */
.container {
  padding: 16px;
}
/* Clear floats */
.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
/* Change styles for cancel button and signup button on extra small screens */
@media screen and (max-width: 300px) {
  .cancelbtn, .signupbtn {
    width: 100%;
  }
}

 

Modal Sign Up Form

<!-- Button to open the modal -->
<button onclick="document.getElementById('id01').style.display='block'">Sign Up</button>
<!-- The Modal (contains the Sign Up form) -->
<div id="id01" class="modal">
  <span onclick="document.getElementById('id01').style.display='none'" class="close" title="Close Modal">times;</span>
  <form class="modal-content" action="/action_page.php">
    <div class="container">
      <h1>Sign Up</h1>
      <p>Please fill in this form to create an account.</p>
      <hr>
      <label for="email"><b>Email</b></label>
      <input type="text" placeholder="Enter Email" name="email" required>
      <label for="psw"><b>Password</b></label>
      <input type="password" placeholder="Enter Password" name="psw" required>
      <label for="psw-repeat"><b>Repeat Password</b></label>
      <input type="password" placeholder="Repeat Password" name="psw-repeat" required>
      <label>
        <input type="checkbox" checked="checked" name="remember" style="margin-bottom:15px"> Remember me
      </label>
      <p>By creating an account you agree to our <a href="#" style="color:dodgerblue">Terms & Privacy</a>.</p>
      <div class="clearfix">
        <button type="button" onclick="document.getElementById('id01').style.display='none'" class="cancelbtn">Cancel</button>
        <button type="submit" class="signup">Sign Up</button>
      </div>
    </div>
  </form>
</div>

 

* {box-sizing: border-box}
/* Full-width input fields */
  input[type=text], input[type=password] {
  width: 100%;
  padding: 15px;
  margin: 5px 0 22px 0;
  display: inline-block;
  border: none;
  background: #f1f1f1;
}
/* Add a background color when the inputs get focus */
input[type=text]:focus, input[type=password]:focus {
  background-color: #ddd;
  outline: none;
}
/* Set a style for all buttons */
button {
  background-color: #4CAF50;
  color: white;
  padding: 14px 20px;
  margin: 8px 0;
  border: none;
  cursor: pointer;
  width: 100%;
  opacity: 0.9;
}
button:hover {
  opacity:1;
}
/* Extra styles for the cancel button */
.cancelbtn {
  padding: 14px 20px;
  background-color: #f44336;
}
/* Float cancel and signup buttons and add an equal width */
.cancelbtn, .signupbtn {
  float: left;
  width: 50%;
}
/* Add padding to container elements */
.container {
  padding: 16px;
}

/* The Modal (background) */
.modal {
  display: none;
 /* Hidden by default */
  position: fixed; 
/* Stay in place */
  z-index: 1; 
/* Sit on top */
  left: 0;
  top: 0;
  width: 100%;
 /* Full width */
  height: 100%; 
/* Full height */
  overflow: auto; 
/* Enable scroll if needed */
  background-color: #474e5d;
  padding-top: 50px;
}
/* Modal Content/Box */
.modal-content {
  background-color: #fefefe;
  margin: 5% auto 15% auto; 
/* 5% from the top, 15% from the bottom and centered */
  border: 1px solid #888;
  width: 80%; 
/* Could be more or less, depending on screen size */
}

/* Style the horizontal ruler */
hr {
  border: 1px solid #f1f1f1;
  margin-bottom: 25px;
}
/* The Close Button (x) */
.close {
  position: absolute;
  right: 35px;
  top: 15px;
  font-size: 40px;
  font-weight: bold;
  color: #f1f1f1;
}
.close:hover,
.close:focus {
  color: #f44336;
  cursor: pointer;
}
/* Clear floats */
.clearfix::after {
  content: "";
  clear: both;
  display: table;
}
/* Change styles for cancel button and signup button on extra small screens */
@media screen and (max-width: 300px) {
  .cancelbtn, .signupbtn {
    width: 100%;
  }
}

 

Tip: You can also use the following javascript to close the modal by clicking outside of the modal content (and not just by using the "x" or "cancel" button to close it):

<script>
// Get the modal
var modal = document.getElementById('id01');
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
    if (event.target == modal) {
        modal.style.display = "none";
    }
}
</script>