There are two ways in which
into HTML pages within HTML tags y using <SCRIPT> and </SCRIPT>
tags into the HTML file.
file having .js extension in the <SCRIPT> and </SCRIPT> tags.
The external file includes should always be in the <head> </head>
tags so that the browser is ready to execute scripts when the user calls
is usually used when the same functionality is used in a number of web
pages in an application. It is quite similar to adding a .CSS file in
a HTML file.
Includes of external files are not supported by Netscape 2 and Explorer