title: How to get unique numbers from Math.random in javascript?
body: <p>When I call this statement 4 times in a loop, it gives me duplicate random numbers.</p>
  
  <pre><code>var a = (parseInt(Math.random() * 4))+1
  </code></pre>
  
  <p>For example, sometimes it gives me 1,3,2,4 (fine!!), but sometimes it produes like 1, 3, 1,4 etc.</p>
  
  <p>How I make sure that when my loop runs 4 times, I get unique set everytime</p>