div.style.fontSize="larger"; : font « Style « JavaScript Tutorial

<html>
<head>
<title>PrettyPretty</title>
<script type="text/javascript">
function bigger() {
  var div = document.getElementById("div1");
  div.style.fontSize="larger";
  div.style.letterSpacing="10px";
  div.style.textAlign="justify";
  div.style.textTransform="uppercase";
  div.style.fontSize="xx-large";
  div.style.fontWeight="900";
  div.style.lineHeight="40px";
}

function smaller() {
   var div = document.getElementById("div1");
   div.style.fontSize="smaller";
   div.style.letterSpacing="normal";
   div.style.textAlign="left";
   div.style.textTransform="none";
   div.style.fontSize="medium";
   div.style.fontWeight="normal";
   div.style.lineHeight="normal";
}
</script>

</head>
<body>
<a href="javascript:bigger();">bigger</a> 
<a href="javascript:smaller();">smaller</a>
<div id="div1">
    <p>p1</p>
    <p>p2</p> 
</div>
</body>
</html>

22.17.font
	22.17.1.	div.style.fontFamily="Verdana";
	22.17.2.	div.style.fontSize="2em";
	22.17.3.	div.style.fontSize="larger";
	22.17.4.	div.style.fontWeight="900";
	22.17.5.	Set font size with form control
	22.17.6.	Set font color with form control