Table’s Width Fixing Hack

I wanted to increase the table size (width). The HTML template was being used by many reports. And my report was not coming into the default size of 100%.
100 percent was not the total screen size available to my report. Instead it was wrapped in a fixed width table. So, I need to find, how to increase the table width of my report only?

For using more than 100 percent for my report data section, I need to increase the size (Width) of the top most tables on the page in which my report was included in a cell (td). After increasing the top most table width, I can set my report's table width to 100 percent.
JavaScript hack for this:

<?php
 echo "<script>
 tbls = document.getElementsByTagName('table');
 for(i=0; i<tbls.length;i++)
 {
  if (i==0)
    tbls[i].style.width = '120%'; // 140 for larger table for data
  else
    tbls[i].style.width = '100%';
  tbls[i].style.overflow = 'auto';
 }
      </script>";
?>