Concentration game
<p>I must do concentration game using JavaScript (without jQuery), HTML and CSS.</p>

<p>I just started programming for the web recently, so I don’t know much about HTML, DOM and JavaScript.</p>

<p>I just can’t make it to work. Comments with  answers about why my code doesn’t work are appreciated.</p>

<h3>Requirements:</h3>

<ul>
<li>It must have 3 levels 
<ul>
<li>Level 3: 104 cards, board:(13x8)</li>
<li>Level 2: 52 cards, board:(13x4)</li>
<li>Level 1: 26 cards, board:(13x2)</li>
</ul></li>
<li>Each incorrect try is -1 point</li>
<li>Correct try is +3 points</li>
<li>Cards directory (cards/) has all cards from card0.jpg to card52.jpg</li>
<li>card0.jpg is default view card</li>
</ul>

<p>Source is here: <a href="http://pastebin.com/Vj1gS2eV" rel="nofollow">http://pastebin.com/Vj1gS2eV</a></p>
