title: javascript 5 random non duplicating integers from 0 - 20
body: <p>What's the best way to generate 5 random non duplicating integers from 0 - 20?</p>
  
  <p>I'm thinking, use Math.random with floor, loop it 5 times, check for duplicates, if duplicate, random again.</p>
  
  <p>What's your way?</p>