//Specify affected tags. Add or remove from list:
 var tgs = new Array( 'div','td','tr');

 //Specify spectrum of different font sizes:
 var szs = new Array( 'xx-small','x-small','small','medium','large','x-large','xx-large' );
//  var szs = new Array( '9px', '10px', '11px', '12px', '13px', '14px' );
 var startSz = 2;

 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 > 6 ) sz = 6;
	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 ];

	}

 }