//=========================
function getElementsByClassName(argClassName, argTagName)
//=========================
// pass:        argClassName = class you're seeking
//              argTagName = [optional] tag name to limit search
//
// returns: array of matching elements
{
         // we'll be searching for the requested class name,
         // optionally bracketed by spaces to handle multiple classes
         var reClassMatch = new RegExp("(^| )" + argClassName + "( |$)");

         // prepare to return the results in an array
         var aResult = new Array();

         // default = search all page elements
         var sTagName = "*";

                 // if one tag was requested, limit the search
                 if (argTagName) sTagName = argTagName;

         // get array of all elements [with matching tag if requested]
         var aEls = document.getElementsByTagName(sTagName);

         // collect elements with matching classNames
         for (var iEl=0; iEl < aEls.length; iEl++)
         {
                 if (reClassMatch.test(aEls[iEl].className))
                 {
                         aResult[aResult.length] = aEls[iEl];
                 }
         }

         // return array of found elements or null
                 if (aResult.length == 0) aResult = null;
         return aResult;
}

var myclass="resizerTest";
var min=80;
var max=120;
function increaseFontSize() {
   var p = getElementsByClassName("resizerTest","div");
   for(i=0;i<p.length;i++) {
      if(p[i].style.fontSize) {
         var s = parseInt(p[i].style.fontSize.replace("%",""));
      } else {
         var s = 100;
      }
      if(s!=max) {
         s += 10;
      }
      p[i].style.fontSize = s+"%"
   }
}
function decreaseFontSize() {
   var p = getElementsByClassName("resizerTest","div");
   for(i=0;i<p.length;i++) {
      if(p[i].style.fontSize) {
         var s = parseInt(p[i].style.fontSize.replace("%",""));
      } else {
         var s = 100;
      }
      if(s!=min) {
         s -= 10;
      }
      p[i].style.fontSize = s+"%"
   }   
}