//  http://www.white-hat-web-design.co.uk/articles/js-fontsize.php

var min=8;
var max=18;
function increaseFontSize() {
   var p = document.body;
  if(p.style.fontSize) {
     var s = parseInt(p.style.fontSize.replace("pt",""));
  } else {
     var s = 12;
  }
  if(s!=max) {
     s += 1;
  }
  p.style.fontSize = s+"px"
}
function decreaseFontSize() {
   var p = document.body;
  if(p.style.fontSize) {
     var s = parseInt(p.style.fontSize.replace("pt",""));
  } else {
     var s = 12;
  }
  if(s!=min) {
     s -= 1;
  }
  p.style.fontSize = s+"px"
}