var min=9;
var max=17;

function changeFontSize(p, amt) {
   if(p == null) {
      p = document.getElementById('BODY');
      var bodyNodes = p.childNodes;
      for (var j=0;j<bodyNodes.length;j++) {
          if (bodyNodes[j] != null && bodyNodes[j].id == 'COL1') {
              p = bodyNodes[j];
              break;
          }
      }
   }
   var s = null;
   if(p.style.fontSize) {
      s = parseInt(p.style.fontSize.replace("px",""));
   } else {
      s = 12;
   }
   if(s!=null) {
      s += amt;
      if ((s>=min && s<=max)){
        p.style.fontSize = s+"px";
      }
   }
   
   var children = p.childNodes;
   for(var i=0;i<children.length;i++) {
      if (children[i] != null && children[i].style && (children[i].nodeName == 'DIV' || children[i].nodeName == 'P')) {
         changeFontSize(children[i], amt);
      }
   }
}