title: Change margin-top with PURE Javascript
body: <p>I wanted to change margin-top of a div which has <code>margin-top:80px;</code> by default. When people scroll the page down it should change its <code>margin-top:40px</code> . This has to be done in JS. I searched on web about this and all i could get is a tutorial on JQuery. Could any one help me with pure JS. I dont want JQuery or any other framework as it loads all code for this simple one. </p>
  
  <p>Any help will be appreciated.</p>
  
  <p>Thank You.</p>