var normalsize= 11;
var maxsize= 17;
var size= 11;


function accessibiliteplus(){
   size++;
   if(size>maxsize)
   size=maxsize;
   document.getElementsByTagName('body')[0].style.fontSize=size+"px";
}
function accessibilitemons(){
   size--;
   if(size<normalsize)
   size=normalsize;
   document.getElementsByTagName('body')[0].style.fontSize=size+"px";
}