The arity property represents the number of declared arguments a function expects to receive.
The arity property is valid when the language attribute of the script tag is set to JavaScript1.2.
<html>
<body>
<script lanuguage="JavaScript1.2">
<!-- function subtract(first, second){
var result = first - second; return result;
}
document.write("arity = " + subtract.arity + "<br>")
document.write("The result of the subtract function is: " + subtract(4,3));
-->
</script>
</body>
</html>