JavaScript 1.2 allows function definitions to be nested within other functions as well. Still, there is a restriction that function definitions may not appear within loops or conditionals. These restrictions on function definitions apply only to function declarations with the function statement.
Example
You can try to run the following example to learn how to implement nested functions
Live Demo
<html>
<head>
<script>
<!--
functionhypotenuse(a,b) {
functionsquare(x){returnx*x;}
returnMath.sqrt(square(a)+square(b));
}
functionsecondFunction() {
varresult;
result=hypotenuse(1,2);
document.write(result );
}
/-->
</script>
</head>
<body>
<p>Clickthe following button to call the function</p>
<form>
<inputtype="button"onclick="secondFunction()"value="CallFunction">
</form>
</body>
</html>