var tgs = new Array( 'div','td','tr'); 
var szs = new Array( 'xx-small','x-small','small','medium','large','x-large','xx-large' ); 
var startSz = 1; 

function ts( trgt,inc ) { 
  if (!document.getElementById) return 
  var d = document,cEl = null,sz = startSz,i,j,cTags; 
   
  sz += inc; 
  if ( sz < 0 ) sz = 0; 
  if ( sz > 2 ) sz = 2; 
  startSz = sz; 
   
  if ( !( cEl = d.getElementById( trgt ) ) ) cEl = d.getElementsByTagName( trgt )[ 0 ]; 

  cEl.style.fontSize = szs[ sz ]; 

  for ( i = 0; i < tgs.length; i++ ) { 
  cTags = cEl.getElementsByTagName( tgs[ i ] ); 
  for ( j = 0; j < cTags.length; j++ ) cTags[ j ].style.fontSize = szs[ sz ]; 
  } 
}