Ending Statements with a Semicolon is necessary?
When we use other programming language then in most of language we put Semicolon at end of statement. With traditional programming languages, like C++ and Java, each code statement has to end with a semicolon.
How to Handle Older Browsers?
Scripts in the head section: Scripts to be executed when they are called, or when an event is triggered, go in the head section. When you place a script in the head section, you will ensure that the script is loaded before anyone uses it.
Scripts in the body section: Scripts to be executed when the page loads go in the body section. When you place a script in the body section it generates the content of the page.
Scripts in both the body and the head section: We can place an unlimited number of scripts in your document, so you can have scripts in both the body and the head section.
To use the external script, point to the .js file in the "src" attribute of the <script> tag: