step by step form

<form id="myForm" method="post" >
  <ul id="steps">
    <li id="step1" class="active">Sign Up</li>
    <li id="step2">More Info</li>
    <li id="step3">Final Step</li>
    <li id="step4">Review</li>
  </ul>
  <fieldset id="set1">
    <input type="email" id="email" name="email" placeholder="Email" required>
    <input type="password" id="password" name="password" placeholder="Password" required>
    <input type='button' id="next1" value='Next' class="next btn" >
  </fieldset>
  <fieldset id="set2">
    <input type="text" id="firstname" name="firstname" placeholder="FirstName">
    <input type="text" id="lastname" name="lastname" placeholder="LastName">
    <input type='button' id="previous2" value='Previous' class="previous btn">
    <input type='button' id="next2" value='Next' class="next btn">
  </fieldset>
  <fieldset id="set3">
    <input type="text" id="facebook" name="facebook" placeholder="Facebook">
    <input type="text" id="other" name="other" placeholder="Other Links">
    <input type='button' id="previous3" value='Previous' class="previous btn">
    <input type='button' id="next3" value='Review' class="next btn">
  </fieldset>
  <fieldset id="review">
    <div id="review">Review Here</div><br>
    <input type='button' id="next4" value='Submit' class="btn">
  </fieldset>
	<fieldset id="submit">
		<h2>Done!<br/>Thank you!</h2>
	</fieldset>
</form>