Function that that would change the paragraph in html body to “largerText”:

<html>
<head>

<script language="JavaScript">
function changeIt(id, newClass) {
document.getElementById("1234").className=newClass;
}
</script>

<style type="text/css">
.regularText {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 10px;
font-style: normal;
font-weight: bold;
color: #0000FF;
}
.largerText {
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 12px;
font-style: normal;
font-weight: bold;
color: #000000;
}
</style>

</head>

<body>
<p id="1234" class="regularText"><a href="#" onClick="changeIt('1234', 'LargerText')">Has it changed?</a></p>
</body>
</html>

Has it changed?