title: Minor issue with two dimensional array
body: <p>I hope you'll help me with this. I have the following piece of code:</p>
  
  <pre><code>var m = new Array([],[]);
  var p=1; 
  while(p&lt;=20){
    x=formula.;
    y=formula.;
    m.push(x);
    m[p-1].push(y) //here spits and error - Uncaught Type Error: m[(p - 1)].push is not a function
    p++;
   ...
  }
  </code></pre>
  
  <p>I have also tried <code>'m[p][0]=x'; 'm[p][1]=y;' but on m[p][0].</code>.. throws an error because the sector 0 was undefined or sth like this. </p>