var tgs = new Array();

var szs = new Array('12pt','14pt','16pt','18pt' );

var startSz = 0;


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 > 4 ) sz = 4;
        
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 ];
    
    }
      
  }