var minimo=100;
var maximo=140;

function increaseFontSize() {
var s =  parseInt(document.getElementById('textovaria').style.fontSize.replace("%",""));
//alert (s);
      if(s<maximo) {
         s = s+10;
      } else {
		 s = maximo;
		 document.getElementById('mas').style.visibility="hidden";
		 document.getElementById('menos').style.visibility="visible";
	  }
       document.getElementById('textovaria').style.fontSize = s+"%" 
	   window.name=s;
}

function decreaseFontSize() {
var s =  parseInt(document.getElementById('textovaria').style.fontSize.replace("%",""));
      if(s>minimo) {
         s -= 10;
      } else {
		 s = minimo;
		 document.getElementById('mas').style.visibility="visible";
		 document.getElementById('menos').style.visibility="hidden";
	  }
       document.getElementById('textovaria').style.fontSize = s+"%" 
	   window.name=s;
}