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HTML 

              
                <section id="contact-form">
  <h2>Contact</h2>
  <form id="contact" name="contact" accept-charset="utf-8">
    <label><span>Name</span><input name="name" type="text" placeholder="Name"/></label>
    <label><span>Email</span><input name="email" type="email" placeholder="Email"/></label>
    <label><span>Message</span><textarea name="message" placeholder="Message"></textarea></label>
    <input name="submit" type="submit" value="Send"/>
  </form>
  <aside>
    <p>Just hit Send on an empty form to see the invalid input animation</p>
    <p>Fill in the form fields to see the success animation (no real validation, any random input will do)</p>
  </aside>
</section>
!

CSS 

              
                html {
  font: 300 100%/1.5 Ubuntu, sans-serif;
  color: #333;
  overflow-x: hidden;
}
h2 {
  margin: 0;
  color: #8495a5;
  font-size: 2.5em;
  font-weight: 300;
}
#contact-form {
  max-width: 1208px;
  max-width: 75.5rem;
  margin: 0 auto;
}
#contact, label, input[name="submit"] {
  position: relative;
}
label > span, input, textarea, button {
  box-sizing: border-box;
}
label {
  display: block;
}
label > span {
  display: none;
}
input, textarea, button {
  width: 100%;
  padding: 0.5em;
  border: none;
  font: 300 100%/1.2 Ubuntu, sans-serif;
}
input[type="text"], input[type="email"], textarea {
  margin: 0 0 1em;
  border: 1px solid #ccc;
  outline: none;
}
input.invalid, textarea.invalid {
  border-color: #d5144d;
}
textarea {
  height: 6em;
}
input[type="submit"], button {
  background: #a7cd80;
  color: #333;
}
input[type="submit"]:hover, button:hover {
  background: #91b36f;
}
@media screen and (min-width: 30em) {
  #contact-form h2 {
    margin-left: 26.3736%;
    font-size: 2em;
    line-height: 1.5;
  }
  label > span {
    vertical-align: top;
    display: inline-block;
    width: 26.3736%;
    padding: 0.5em;
    border: 1px solid transparent;
    text-align: right;
  }
  input, textarea, button {
    width: 73.6263%;
    line-height: 1.5;
  }
  textarea {
    height: 10em;
  }
  input[type="submit"], button {
    margin-left: 26.3736%;
  }
}
@media screen and (min-width: 48em) {
  #contact-form {
    text-align: justify;
    line-height: 0;
  }
  #contact-form:after {
    content: '';
    display: inline-block;
    width: 100%;
  }
  #contact-form h2 {
    margin-left: 17.2661%;
  }
  #contact-form form, #contact-form aside {
    vertical-align: top;
    display: inline-block;
    width: 65.4676%;
    text-align: left;
    line-height: 1.5;
  }
  #contact-form aside {
    width: 30.9353%;
  }
}
!

JS 

              
                var form = $('#contact'),
    submit = form.find('[name="submit"]');

form.on('submit', function(e) {
  e.preventDefault();
  
  // avoid spamming buttons
  if (submit.attr('value') !== 'Send')
    return;
  
  var valid = true;
  form.find('input, textarea').removeClass('invalid').each(function() {
    if (!this.value) {
      $(this).addClass('invalid');
      valid = false;
    }
  });
  
  if (!valid) {
    form.animate({left: '-3em'},  50)
        .animate({left:  '3em'}, 100)
        .animate({left:    '0'},  50);
  } else {
    submit.attr('value', 'Sending...')
          .css({boxShadow: '0 0 200em 200em rgba(225, 225, 225, 0.6)',
                backgroundColor: '#ccc'});
    // simulate AJAX response
    setTimeout(function() {
      // step 1: slide labels and inputs
      // when AJAX responds with success
      // no animation for AJAX failure yet
      form.find('label')
          .animate({left: '100%'}, 500)
          .animate({opacity: '0'}, 500);
    }, 1000);
    setTimeout(function() {
      // step 2: show thank you message after step 1
      submit.attr('value', 'Thank you :)')
            .css({boxShadow: 'none'});
    }, 2000);
    setTimeout(function() {
      // step 3: reset
      form.find('input, textarea').val('');
      form.find('label')
          .css({left: '0'})
          .animate({opacity: '1'}, 500);
      submit.attr('value', 'Send')
            .css({backgroundColor: ''});
    }, 4000);
  }
});
!
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