var tgs = new Array( 'div','td','tr', 'p', 'li'); 
var szs = new Array( '13px','18px' ); 
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 > 1 ) sz = 1; 
       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 ]; 
       } 
}

function un() {
document.getElementById('uns').style.textDecoration='none';
document.getElementById('un').style.textDecoration='underline';
}

function uns() {
document.getElementById('un').style.textDecoration='none';
document.getElementById('uns').style.textDecoration='underline';
}