function SetFontSize( iSize ) {
 p_size = 12;
 h_size = 26;
 switch (iSize) {
  case "1":
   p_size = 11;
   h_size = 24;
   break;
  case "2":
   p_size = 12;
   h_size = 26;
   break;
  case "3":
   p_size = 15;
   h_size = 29;
   break;
 }

   var p = document.getElementsByTagName('p');
   for(i=0;i<p.length;i++) {
      p[i].style.fontSize = p_size+"px"
   }
   var p = document.getElementsByTagName('h1');
   for(i=0;i<p.length;i++) {
      p[i].style.fontSize = h_size+"px"
   }
}