title: Add css using Onchange
body: <p>How change code CSS` in JavaScript?</p>
  
  <p><strong>HTML :</strong></p>
  
  <pre><code>&lt;input type="text" name="text_field"  value="text" id ="hd" /&gt;
  
  &lt;div id="color"&gt;
      &lt;input type="text" name="color" class ="border-bottom" value=""/&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p><strong>Javascript :</strong></p>
  
  <pre><code>$(document).ready(function() {
       $('#color input').change(function(){
            var css = $(this).attr("class");
            var z   = string(css);  // change type to string
            var x   = z+': 1px solid'; // mix 
            $("#hd").css(css,$(this).val());
       });
  });
  </code></pre>
  
  <p>I need write <code>1px solid</code> in field, I try mix from <code>border-bottom</code> and <code>1px solid</code> to new variable (<code>border-bottom : 1px solid</code>), then I just input color type like red/blue/dll.</p>
  
  <p>Please see here for more understanding <a href="https://jsfiddle.net/1Lmhj3xp/1/" rel="nofollow">https://jsfiddle.net/1Lmhj3xp/1/</a></p>