External Scripting:
If the functionality to be defined is used in various HTML documents then its better to keep
that functionality in a separate Javascript file and then include that file in your HTML docx.
E.g.
<html>
<head>
<title></title>
<script src="any_file.js" type="text/javascript">
</script>
</head>
<body>
<input type="button" onclick="External();" value="Click here">
</body>
</html>
---------------------------------------------
Internal Scripting
The code can be written directly into the HTML document.
e.g.
<html>
<head>
<title></title>
<script type="text/javascript">
function internal(){
alert("Internal Script");
}
</script>
</head>
<body>
<form>
<input type="button" onclick="internal();" value="Click here">
</form>
</body>
</html>
--------------------
Event Handler:
Event handlers are simple defined functions which can be called against any mouse or
keyboard event.
