title: Generating all possible combinations of strings
body: <p>I am trying to generate all possible combinations of a string.</p>
  
  <p>e.g. for the list below: a1q5z!H9, b1q5z!H9, c1q5z!H9, d1q5z!H9, a2q5z!H9 ... etc </p>
  
  <p>Rather than make lots of nested loops, I thought I would try something clever with MODULO ... but hit a wall.</p>
  
  <p>This is the Javascript I have come up with - any pointers to how I might go on?</p>
  
  <pre><code>var c = [
    ['a', 'b', 'c', 'd'],
    ['1', '2', '3', '4'],
    ['q', 'w', 'e', 'r'],
    ['5', '6', '7', '8'],
    ['z', 'x', 'c', 'v'],
    ['!', '"', '£', '$'],
    ['H', 'J', 'K', 'L'],
    ['9', '8', '7', '6'],
  ];
  
  var o = document.getElementById('output');
  var pw = "";
  var chars = c.length;
  
  for( var i = 0; i &lt;20; i++)
  {
    pw = ""
    for(var j = 0; j &lt; chars; j++ )
      {
        pw += c[j][i%4];
      }
    op(pw);
  }
  
  function op(s)
  {
    o.innerHTML = o.innerHTML + "&lt;br&gt;" + s;
  }
  </code></pre>
  
  <p>This just outputs the first 20 in the list, but repeats ... I nearly have it but not quite. Any help or pointers appreciated.</p>