A good first step in learning Javascript is learning its implementation. The html <script> element is your document's gateway to Javascript. You can apply the <script> element in your <head> or <body> elements at will, which gives you a fair amount of script placement options directly inside your document.
Alternately you can choose to use the <script> element to bind an external Javascript file and all of its code to your document. Most Javascript authors prefer externalizing their code to call on functions waiting in the external file. Externalizing your code means you can reuse the same code on many different web pages, it makes your html code appear slimmer and cleaner, and it helps one in beginning to understand code modularity. If you are used to CSS it is much like externalizing your CSS into style sheets.
Binding external Javascript files(myFile.js) to your document is essentially the same as having the code sitting right there in the document as in the first code example above. To make it work exactly as the first example, your external Javascript file would need to have this code in it to be able to write "mySentence":
