When I declare table width as 100%, why does it not go across the whole screen?

Here is my script:



<table width='100%' cellspacing='0' cellpadding='0' border='0'>
<tr width='100%'>
<td width='100%' bgColor='black'>
<font color='white'>This is the text</font>


When I put this script on my page, I always end up having white spaces on both sides of the table. Can anyhelp me fix this so that the table starts at the very top of the screen and stretches from the left of the screen to the right of the screen?