Using the <script> Element to Link External Files
The second way is to place JavaScript code in an external file and import it into the document. The second method is preferred because, with large programs, it is hard to maintain everything in an HTML document. JavaScript files have the file extension ".js". An example is:
<script src="myprogram.js"></script>
Although all JavaScript code should be in a .js file because our programs are short, we'll place code directly within a <script> tag. We'll use external .js files in the next course.
Attributes
Deprecated attributes
charset If present, its value must be an ASCII case-insensitive match for "utf-8". It’s unnecessary to specify the charset attribute,
because documents must use UTF-8, and the script element inherits its character encoding from the document.
language Like the type attribute, this attribute identifies the scripting language in use. Unlike the type attribute,
however, this attribute’s possible values were never standardized. The type attribute should be used instead.