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HTML 

              
                <header>
  <input type="checkbox" id="json-toggle" class="toggle">
  <label for="json-toggle">JSON Mode</label>
</header>

<main>
  <div class="form">
    <div class="fieldset fieldset__options">
      <label>Select a transition</label>
      <label><input type="radio" name="transition" value="1" checked="checked"><code>linear 500ms</code></label>
      <label><input type="radio" name="transition" value="2"><code>linear 200ms</code></label>
      <label><input type="radio" name="transition" value="3"><code>ease 300ms</code></label>
      <label><input type="radio" name="transition" value="4"><code>ease-in 300ms</code></label>
      <label><input type="radio" name="transition" value="5"><code>ease-out 300ms</code></label>
      <label><input type="radio" name="transition" value="6"><code>cubic-bezier(.05, .69, .14, 1) 500ms</code></label>
      <label><input type="radio" name="transition" value="custom">Custom</label>
    </div>
    
    <div class="fieldset">
      <label for="id">Custom transition (timing speed)</label>
      <input type="text" placeholder="e.g. cubic-bezier(.03,.43,.95,.66) 500ms" name="custom-transition" value="cubic-bezier(.03,.43,.95,.66) 500ms">
    </div>
    
    <div class="fieldset">
      <label for="id">Some other field</label>
      <input type="text">
    </div>
    
    <div class="fieldset">
      <label for="id">Some other field</label>
      <input type="text">
    </div>
    
    <h3>What is this?</h3>
    <p>Experimenting with different transition speeds and methods for toggling in JSON configuration mode for a form. Prototype for <a href="http://mesosphere.com">Mesosphere</a> where we have a JSON option in DC/OS to configure and launch Docker containers.</p>
    <p>Some good reading:
      <ul>
        <li><a href="http://valhead.com/2016/05/05/how-fast-should-your-ui-animations-be/">How fast should your UI animations be?</a></li>
        <li><a href="https://www.smashingmagazine.com/2016/08/css-animations-motion-curves/">CSS Animation with motion curves</a></li>
        <li><a href="https://blog.alexmaccaw.com/css-transitions">All you need to know about CSS transitions</a></li>
        <li><a href="http://cubic-bezier.com/#.17,.67,.83,.67">Cubic Bezier tool</a></li>
      </ul>
    </p>
  </div>

  <div class="json">
    Hi I'm JSON mode
  </div>
</main>
!

CSS 

              
                // Transitions
$transitions: 
  linear 500ms,
  linear 200ms,
  ease 300ms,
  ease-in 300ms,
  ease-out 300ms,
  cubic-bezier(.05, .69, .14, 1) 500ms;

@for $i from 1 through length($transitions) {
  .transition-#{$i} {
    transition: nth($transitions, $i);
  }
}

// Other variables
$header: 20px;
$json-width: 50%;
$padding: 20px;

// JSON mode styles
.json {
  background: #252b3a;
  box-sizing: border-box;
  color: #fff;
  flex: 0 0 $json-width;
  font-family: monospace;
  font-size: 120%;
  margin-right: -$json-width;
  padding: $padding;
  transition-property: all;
}

.json--on {
  margin-right: 0;
}

// Form styles
.form {
  flex: 1;
  overflow: scroll;
  padding: $padding;
  
  .fieldset {
    clear: both;
    margin: 0 0 $padding*2;
  }
  
  .fieldset__options label {
    margin-right: 10px;
    
    input {
      margin-right:5px;
      width: auto;
    }
  }
  
  label {
    display: block;
    font-size: .8em;
    margin-bottom: $padding/2;
    text-transform: uppercase;
  }
  
  input {
    background: #f2f2f2;
    border: 2px solid transparent;
    border-radius: 5px;
    box-sizing: border-box;
    padding: $padding/2;
    width: 100%;
    
    &:focus {
      border: 2px solid #9351e5;
      outline: none;
    }
  }
}

// General styles
body {
  color: #333;
  font-family: -apple-system, "Helvetica Neue";
  height: 100%;
  line-height: 1.4;
}

h3 {
  margin-bottom: 0;
}

p,
ul,
ol {
  color: #555;
  font-size: 14px;
}

code {
  background-color: #f9f2f4;
  border-radius: 4px;
  color: #c7254e;
  font-size: 90%;
  padding: 2px 4px;
}

header {
  background: #f9f9f9;
  border-bottom: 1px solid #eaebed;
  height: $header;
  position: fixed;
  padding: $padding;
  text-align: right;
  width: 100%;
}

main {
  display: flex;
  flex-direction: row;
  flex: 1;
  overflow: hidden;
  padding-top: 60px;
}

// Toggle styles
.toggle {
  margin-left: -999px;
  visibility: hidden;
}

.toggle + label {
  border-radius: 60px;
  cursor: pointer;
  float: left;
  font-size: 12px;
  height: 10px;
  outline: none;
  padding: 6px;
  position: relative;
  text-indent: 40px;
  user-select: none;
}
.toggle + label:before,
.toggle + label:after {
  content: "";
  bottom: 1px;
  display: block;
  left: 1px;
  position: absolute;
  top: 1px;
  width: 40px;
}
.toggle + label:before {
  background-color: #f1f1f1;
  border: 1px solid #eaebed;
  border-radius: 60px;
  right: 1px;
  transition: background 0.4s;
}
.toggle + label:after {
  background-color: #fff;
  border-radius: 100%;
  box-shadow: 0 2px 5px rgba(0, 0, 0, .3);
  transition: margin 0.4s;
  width: 20px;
}
.toggle:checked + label:before {
  background-color: #8ce196;
}
.toggle:checked + label:after {
  margin-left: 20px;
}
!

JS 

              
                $('.toggle').on('click', function(e) {
  
  $('.json').removeClass (function (index, css) {
    return (css.match (/(^|\s)transition-\S+/g) || []).join(' ');
});
  $('.json').removeAttr('style');
  var transition = $("input[name='transition']:checked").val();
  
  if (transition == "custom") {
    var customTransition = $("input[name='custom-transition']").val();
    $('.json').attr('style','transition: ' + customTransition);
  } else {
    $('.json').addClass('transition-'+transition);
  }
  
  $('.json').toggleClass('json--on');

});
!
999px

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