Use External Js File

When you have lots of JavaScript functions and you plan to use them on many web pages, it is always advisable to keep them in a separate file, and then include that file on every page where those functions are required. This way, you can better organize them, you don't have to copy/paste the code again and again (imagine if it runs to 100 or more lines!!), and you'll be forced to write more generalized code for better integration and scalability.

Besides, enclosing the common JavaScript routines in external files keeps your web pages uncluttered and search engine spiders and crawlers are able to reach the important content easily. They don't have to shuffle through tens of lines of scripts.

It's very simple. Use any text editor of your liking (if you hand-code your HTML, you can use the same editor that you use for your HTML editing). Write the required code, and save the file with .js (dot js) extension.

I'm going to give you a small example.

Suppose your JavaScript file is "myjfuncs.js".

and it has a function to return the bigger number of the two supplied as parameters (you can simply start with the function, no need to write <script> or some other stuff):

function bigger(num1, num2) { var holdbig; if (num1<num2) { holdbig=num2; } else if(num1>num2) { holdbig=num1; } else { holdbig=num1; } return holdbig; }

In a similar manner, we can have

function smaller(num1, num2) {

}

When we want to use this precious file full of JavaScript functions, we use this line:

<script language="JavaScript" type="text/javascript" src="myjfuncs.js"> </script>

So when we use one of its functions in a JavaScript:

<script language="javascript">

var n1=90; var n2=7; alert ("The bigger number is: " + bigger(n1, n2));

</script>

In this way, we can use all the complex functions contained in the myjfuncs.js file.