nie korzystałem wcześniej z canvas
próbowałem z position:relative, ale łapał od śdroka strony (od body?)
//edit
eh, macie rozwiązanie
<div style="border:1px solid #444; height: 300px; width:300px; padding: 10px; position:absolute ; display: table; top:100px; left: 100px;" id="div_sala2">
<span style=" border:1px solid #444; clear: inherit; position: absolute; display: block; height: 25px; width:25px; top:0; left:0" onclick="alert('0x0')">0
</span> <span style=" border:1px solid #444; clear: inherit; position: absolute; display: block; height: 25px; width:25px; top:50; left:50" onclick="alert('50x50')">5
</span> <span style=" border:1px solid #444; clear: inherit; position: absolute; display: block; height: 25px; width:25px; top:100; left:100" onclick="alert('100x100')">100
</span>
<span style=" border:1px solid #444; clear:inherit; position: absolute; display: block; height: 25px; width:25px; top:0; left:100" onclick="alert('0x100')">x10
</span> <span style=" border:1px solid #444; clear:inherit; position: absolute; display: block; height: 25px; width:25px; top:100; left:0" onclick="alert('100x0')">10x
</span>