In a web page, how can you insert JavaScript code into HTML so that the browser can execute it?

Introduction / Context:
JavaScript is the main scripting language used on web pages to add interactivity, form validation, animations, and application logic. For the browser to run JavaScript code, it must be inserted into the HTML document in a way that the browser recognizes as executable script. This question checks whether you know the correct mechanisms for including JavaScript, both inline and through external files, which is a basic but essential skill for any front end or full stack developer.

Given Data / Assumptions:
- We are working with standard HTML documents loaded in a web browser.
- JavaScript should run automatically when the page loads or when events occur.
- The question seeks the correct way to insert code, not how to write JavaScript logic itself.
- External .js files are supported by the browser.

Concept / Approach:
Browsers treat code as JavaScript only when it is enclosed in script tags or linked via script tags that reference external files. Inline code is placed between opening and closing script tags, usually in the head or body. External code is placed in .js files, and the HTML uses a script tag with a src attribute pointing to that file. Options that mention style tags, comments, or renaming files are misleading because they do not match how browsers interpret resources.

Step-by-Step Solution:
Step 1: Recall that script tags are the standard way to embed JavaScript in HTML. Step 2: Remember that external .js files are referenced using a script tag with a src attribute. Step 3: Examine each option and check which one mentions script tags and .js files in the correct way. Step 4: Choose the option that clearly states that JavaScript belongs inside script tags or in external .js files linked with script tags.

Verification / Alternative check:
You can verify the correct approach by creating a simple HTML page with a script tag that shows an alert message. When the page loads, the alert confirms that the browser executed the code. Then, move the same code into an external file and include it with a script tag that uses src. The behavior remains the same, confirming that both inline and external methods are valid as long as they use script tags.

Why Other Options Are Wrong:
Option B is wrong because renaming an HTML file to a class file does not make it JavaScript and will confuse the browser. Option C is incorrect because style tags are for CSS, not for JavaScript. Option D is unrealistic because typing code into the address bar is not how scripts are deployed on a site. Option E is misleading because wrapping code in comment tags hides it from the browser, preventing execution rather than enabling it.

Common Pitfalls:
One common mistake is forgetting to place script tags in the correct location relative to the DOM, which can cause scripts to run before elements are loaded. Another pitfall is mixing CSS and JavaScript in the same tag type, which makes the code invalid. Developers should also remember that external scripts improve maintainability and caching, and they should prefer that approach for larger code bases while keeping small snippets inline only when necessary.

Final Answer:
JavaScript code is inserted into HTML by placing it inside script tags in the head or body or by linking an external .js file using a script tag.