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

    //Specify spectrum of different font sizes:
    var szs = new Array('xx-small','x-small','small','medium','large','x-large','xx-large' );
    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 > 5 ) sz = 5;
    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 ];
    }
  }