Final answer:
JavaScript can be included in both the <head> and <body> sections of an HTML document, with specific placement depending on performance and behavior needs.
Step-by-step explanation:
A JavaScript tag can be injected into an HTML document in a few different places. The most common places to insert JavaScript are within the <head> section or at the end of the <body> section.
When a script is placed in the <head> section, the JavaScript is loaded before the body of the page. This placement is typically for scripts that do not affect the initial page content. Conversely, placing scripts just before the closing </body> tag can lead to a faster page load because HTML displays before the script is executed. In certain cases, scripts may also be included directly within HTML elements to respond to events such as user input or clicks.
Therefore, the complete answer would be both within the <head> the section and within the <body> section, wherever appropriate to the script's purpose. This provides flexibility to optimize performance and page behavior.