<form id="signup" action="somewhere" method="POST">
    <ul id="section-tabs">
      <li class="current active"><span>1.</span> Creds</li>
      <li><span>2.</span> Deets</li>
      <li><span>3.</span> Settings</li>
      <li><span>4.</span> Last Words</li>
    </ul>
  <div id="fieldsets">
  <fieldset class="current">
    <label for="email">Email:</label>
    <input name="email" type="email" class="required email" />
    <label name="password" for="password">Password:</label>
    <input type="password" minlength="10" class="required">
  </fieldset>
  <fieldset class="next">
    <label for="username">Username:</label>
    <input name="username" type="text">
    <label for="bio">Short Bio:</label>
    <textarea name="bio" class="required"></textarea>
  </fieldset>
  <fieldset class="next">
    <label for="interests">Basic Interests:</label>
    <textarea name="bio"></textarea>
    <p>Receive newsletter?<br>
      <input type="radio" name="newsletter" value="yes"><label for="newsletter">yes</label>
      <input type="radio" name="newsletter" value="no"><label for="newsletter">no</label>
    </p>
  </fieldset>
  <fieldset class="next">
    <label for="referrer">Referred by:</label>
    <input type="text" name="referrer">
    <label for="phone">Daytime Phone:</label>
    <input type="tel" name="phone">
  </fieldset>
  <a class="btn" id="next">Next Section ▷</a>
  <input type="submit" class="btn">
  </div>
</form>

@import url(https://fonts.googleapis.com/css?family=Merriweather+Sans:300);
@import url(https://fonts.googleapis.com/css?family=Merriweather+Sans:700);
 
 
body {
  background: url(http://farm5.staticflickr.com/4139/4825532997\_7a7cd3d640\_b.jpg);
  background-size: cover;
  height: 100%;
  font-family: 'Merriweather Sans', sans-serif;
  color: #666;
}
 
#signup {
  width: 600px;
  height: auto;
  padding: 20px;
  background: #fff;
  margin: 80px auto;
  position: relative;
  min-height: 300px;
}
#fieldsets {
  position: absolute;
  top: 0px;
  left: 0px;
  width: 100%;
  height: 100%;
  padding: 20px;
  box-sizing: border-box;
  overflow: hidden;
}
input[type=text],
input[type=email],
input[type=password],
input[type=tel],
textarea {
  display: block;
  -webkit-appearance: none;
  -moz-appearance: none;
  width: 100%;
  box-sizing: border-box;
  border: 1px solid #ddd;
  padding: 8px;
  margin-bottom: 8px;
  position: relative;
  &:focus {
    outline: none;
    border: 1px solid darken(#2cbab2,10%);
  }
}
 
input[type=radio]{
  margin: 6px;
  display: inline-block;
}
fieldset {
  border: none;
  position: absolute;
  left: -640px;
  width: 600px;
  padding: 10px 0;
  transition: all 0.3s linear;
  -webkit-transition: all 0.3s linear;
  -moz-transition: all 0.3s linear;
  -ms-transition: all 0.3s linear;
  opacity: 0;
  &.current {
    left: 20px;
    opacity: 1;
  }
  &.next {
    left: 640px;
  }
}
input[type=submit] {
  display: none;
  border: none;
}
#section-tabs {
  font-size: 0.8em;
  height: 50px;
  position: relative;
  margin-top: -50px;
  margin-bottom: 50px;
  padding: 0;
  font-weight: bold;
  list-style: none;
  text-transform: uppercase;
  li {
    color: #a7a7a7;
    span {
      color: #bababa;
    }
    cursor: not-allowed;
    &.active {
      color: #444;
      cursor: pointer;
    }
    border-left: 1px solid #aaa;
    text-decoration: none;
    padding: 0 6px;
    float: left;
    width: 25%;
    box-sizing: border-box;
    text-align: center;
    font-weight: bold;
    line-height: 30px;
    background: #ddd;
    position: relative;
    &:after {
      content: "";
      display: block;
      margin-left: 0;
      position: absolute;
      left: 0;
      top: 0;
    }
    &.current {
      opacity: 1;
      background: #fff;
      z-index: 999;
      border-left: none;
      &:after {
        border: 15px solid transparent;
        border-left: 15px solid #2cbab2;
      }
    }
  }
}
.error {
  color: #bf2424;
  display: block;
}
input.error, textarea.error {
  border-color: #bf2424;
  &:focus {
    border-color: #bf2424;
  }
}
label.error {
    margin-bottom: 20px;
}
input.valid {
  color: green;
}
label.valid {
  position: absolute;
  right: 20px;
}
input+.valid, textarea+.valid {
  display: none;
}
.valid+.valid {
  display: inline;
  position: absolute;
  right: 10px;
  margin-top: -36px;
  color: green;
}
 
.btn {
  border: none;
  padding: 8px;
  background: #2cbab2;
  cursor: pointer;
  transition: all 0.3s;
  -webkit-transition: all 0.3s;
  -moz-transition: all 0.3s;
  &:hover {
     background: darken(#2cbab2, 6%);
  }
  color: #fff;
  position: absolute;
  bottom: 20px;
  right: 20px;
  font-family: 'Merriweather Sans', sans-serif;
}

$("body").on("keyup", "form", function(e){
  if (e.which == 13){
    if ($("#next").is(":visible") && $("fieldset.current").find("input, textarea").valid() ){
      e.preventDefault();
      nextSection();
      return false;
    }
  }
});
 
 
$("#next").on("click", function(e){
  console.log(e.target);
  nextSection();
});
 
$("form").on("submit", function(e){
  if ($("#next").is(":visible") || $("fieldset.current").index() < 3){
    e.preventDefault();
  }
});
 
function goToSection(i){
  $("fieldset:gt("+i+")").removeClass("current").addClass("next");
  $("fieldset:lt("+i+")").removeClass("current");
  $("li").eq(i).addClass("current").siblings().removeClass("current");
  setTimeout(function(){
    $("fieldset").eq(i).removeClass("next").addClass("current active");
      if ($("fieldset.current").index() == 3){
        $("#next").hide();
        $("input[type=submit]").show();
      } else {
        $("#next").show();
        $("input[type=submit]").hide();
      }
  }, 80);
 
}
 
function nextSection(){
  var i = $("fieldset.current").index();
  if (i < 3){
    $("li").eq(i+1).addClass("active");
    goToSection(i+1);
  }
}
 
$("li").on("click", function(e){
  var i = $(this).index();
  if ($(this).hasClass("active")){
    goToSection(i);
  } else {
    alert("Please complete previous sections first.");
  }
});