title: Every Time on a button click, generate a UNIQUE random number in a range of 1 - 100 - JavaScript
body: <p>I have a function. Every time I call the function, it should return a UNIQUE (for example, if I call this function 90 times, it should have given 90 different numbers) random number under 100. </p>
  
  <p>I am currently doing </p>
  
  <pre><code>var randomNumber = Math.floor(Math.random() * 100);
  </code></pre>
  
  <p>But, it's not returning unique numbers. It's only returning random numbers. </p>
  
  <p>Thanks in advance.</p>
  
  <p><strong>Edit:</strong> 
  It should return some alert after calling 100 times.</p>