title: how to make height of a div responsive?
body: <p>I want a div where if the height of that div exceeds 450px there will be scroller. I am able to do that by adding a classname say, fixedScroll_450 to the div. </p>
  
  <pre><code>&lt;div class="fixedScroll_450" id="content"&gt;&lt;/div&gt;
  </code></pre>
  
  <p>Now the div's content will be generated dynamically, and if it exceeds 450px of height there will be scroller otherwise not. 
  Now for the styling I add in the class</p>
  
  <pre><code>.fixedScroll_450{
     min-height: 450px;
     max-height: 450px;
     width: 100%;
     margin: 0;
     overflow-y: auto;
   }
  </code></pre>
  
  <p>it is working fine.. But i want to give the height in percentage value not in pixel. But</p>
  
  <pre><code> .fixedScroll_450{
     min-height: 30%;
     max-height: 30%;
     width: 100%;
     margin: 0;
     overflow-y: auto;
   }
  </code></pre>
  
  <p>is not working. the height set with 100% with this code. plz guide me..</p>