title: How can I use an element from an object in array in Javascript
body: <p>I have an arrayList with objects. And those objects have random numbers. I want to use some of them after, but I don't know how I can get to it. 
  here's my code : </p>
  
  <pre><code>     for(var l=0; l&lt;20; l++){
          o.x=Math.random();
          o.y=Math.random();
          tab3[l]=[o.x,o.y];
  
        }
  </code></pre>
  
  <p>So I want to use for example o.x from the first object in the array (tab[0]). How is that possible? and if I wish to add some more elements, like o.z to tab[0], how can I do that ?</p>