How to use Random script

Question

I have 3 Google Adsense scripts with 300 x 250 - 160 x 600 - 728 x 90

How I do for each time the page is loaded 1 of these scripts is shown?

I would like each page Reload to be shown 1 script.

Example:

I own the one that is used for iframe, but in the case of Adsense I need to use the full script.

    <script language="JavaScript">
    var quotes=new Array()
     quotes[0]='<iframe frameborder="0" height="250" name="videoplayer" 
    scrolling="no" src="http://" style="border: 0px #FFFFFF none;" width="300">
   </iframe>'
      quotes[1]='<iframe frameborder="0" height="250" name="videoplayer" 
      scrolling="no" src="http://" 
      style="border: 0px #FFFFFF none;" width="300"></iframe>'
      quotes[2]='<iframe frameborder="0" height="250" name="videoplayer" 
      scrolling="no" src="http://" style="border: 0px #FFFFFF none;" width="300"></iframe>'
      var whichquote=Math.floor(Math.random()*(quotes.length))
      document.write(quotes[whichquote])
      </script>

Blocks I want to use in mo Randon

       <script async 
       src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js">
        </script>
         <!-- lateral -->
         <ins class="adsbygoogle"
     style="display:inline-block;width:300px;height:250px"
     data-ad-client="ca-pub-2068602933738629"
      data-ad-slot="8173528505"></ins>
            <script>
          (adsbygoogle = window.adsbygoogle || []).push({});
         </script>

         <script async 
       src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js">
        </script>  <ins
         class="adsbygoogle"
          style="display:inline-block;width:160px;height:600px"
            data-ad-client="ca-pub-2068602933738629"
             data-ad-slot="2353050305"></ins> <script>(adsbygoogle = 
         window.adsbygoogle || []).push({});</script>

              <script async 

          src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js">
               </script>
           <!-- celular -->
           <ins class="adsbygoogle"
           style="display:inline-block;width:320px;height:100px"
           data-ad-client="ca-pub-2068602933738629"
          data-ad-slot="6337832563"></ins>
            <script>
           (adsbygoogle = window.adsbygoogle || []).push({});
            </script>

Answer 1

The Math.random() gives you a decimal number between 0 and 1.

To have a number between 0 and 2 you can do Math.random() * 2, ie maximum is 2 minimum is 0.

To have only integers (to use as array input for example) you can use Math.round().

function gerarNumero(){
    return Math.round(Math.random() * 2);
}

If you want to ensure that a number is only drawn once every iteration of the other numbers is not enough to do this only in the browser, you have to have server logic.

An example would be like this:

(function() {
  var script = document.createElement('script');
  script.src = "https://pagead2.googlesyndication.com/pagead/js/adsbygoogle.js";
  document.body.appendChild(script);
  (adsbygoogle = window.adsbygoogle || []).push({});

  function gerarNumero(max) {
    return Math.round(Math.random() * max);
  }
  var quotes = [
    '<ins class="adsbygoogle" style="display:inline-block;width:160px;height:600px" data-ad-client="ca-pub-2068602933738629" data-ad-slot="2353050305"></ins>',
    '<ins class="adsbygoogle" style="display:inline-block;width:300px;height:250px" data-ad-client="ca-pub-2068602933738629" data-ad-slot="8173528505"></ins>',
    '<ins class="adsbygoogle" style="display:inline-block;width:320px;height:100px" data-ad-client="ca-pub-2068602933738629" data-ad-slot="6337832563"></ins>'
  ];
  var index = gerarNumero(quotes.length - 1);
  var adDiv = document.createElement('div');
  adDiv.innerHTML = quotes[index]
  document.body.appendChild(adDiv.children[0]);
})();