External JavaScript

Importing JavaScript from an external file can be prudent — rather than embedding the JavaScript code in the web page.

These situations generally indicate a preference for importing the JavaScript from an external file.

1. The JavaScript is used on more than one page. It's easier to update one file to import than it is to keep track of and update every page where the JavaScript is located.

2. The JavaScript is for a WordPress post or page. WordPress is inclined to insert <br> and/or </p><p> tags where linebreaks occur. Multiline JavaScript is virtually guaranteed to break. Importing is the workaround.

If the JavaScript is used only once, and there are no special cases to indicate otherwise, it generally is more efficient to embed the JavaScript into the web page.

When JavaScript is saved in an external file for importing into web pages, remove the beginning and ending script tags. As an example, this JavaScript:

<script type="text/javascript">
alert("Hello, World!");
</script>

Would be saved in the file as:

alert("Hello, World!");

Files to be imported conventionally are named with .js file name extensions. But it's not a requirement. The file name extension (or its absence) can be anything the server will respond with — .txt, .php, .html, etc.

Here's an example of code to import JavaScript from an external file:

<script type="text/javascript" src="http://example.com/jsfile.js"></script>

If it's not a WordPress page and the CMS you're using has no considerations that would indicate otherwise, importing can be done with the code in multiple lines:

<script 
   type="text/javascript" 
   src="http://example.com/jsfile.js">
</script>

In all cases, replace http://example.com/jsfile.js with the URL to the external file you wish to import into your web page.

Will Bontrager