title: storing table cell content into js array
body: <p>I need to store table cell content into array using tr and td indexes like this:</p>
  
  <pre><code>myArray[tr_idx][td_idx]='value';
  </code></pre>
  
  <p>It is not required to store data of all of cells in array but only several with a special content, but if i use indexes as a keys of the array i'll have many empty array elements.</p>
  
  <p>e.g.</p>
  
  <pre><code>myArray[2][3]='data1';
  myArray[4][3]='data2';
  
  alert (myArray.toSource()) -&gt; [, , [, , , "data1"], , [, , , "data2"]]
  </code></pre>
  
  <p>maybe there is another suitable way of storing such type of data?</p>