Modern Web Design with HTML5, CSS3, and JavaScript - Loading JavaScript once a Page is Loaded

The video tutorial explains the importance of the DOM loading order in JavaScript. It highlights how placing script tags in the head section can lead to null values when accessing page elements before the body loads. The tutorial introduces the DOMContentLoaded event, which ensures the DOM is fully loaded before executing scripts. It also covers using event listeners with the window object and discusses variable scope, emphasizing the difference between global and block-scoped variables.

Why might a JavaScript script placed in the head section fail to access DOM elements?

• The script is executed before the DOM is fully loaded.

• The script is missing a semicolon.

• The script is not linked properly.

• The script is written in an outdated version of JavaScript.

What does the DOMContentLoaded event signify?

• The JavaScript code has finished executing.

• The initial HTML document is fully loaded and parsed.

• The browser has completed rendering the page.

• All images and stylesheets have finished loading.

How does jQuery typically handle DOM interactions?

• By using the DOMContentLoaded event to ensure the DOM is ready.

• By executing scripts immediately after the head section.

• By loading scripts asynchronously.

• By using inline JavaScript within HTML.

What is the purpose of adding an event listener to the window object for DOMContentLoaded?

• To delay the execution of JavaScript until the DOM is ready.

• To prevent JavaScript from running altogether.

• To load external scripts dynamically.

• To execute JavaScript before the DOM is loaded.

How can you manage a variable to be accessible globally after the DOM is loaded?

• Declare it outside the function and reassign it within the DOMContentLoaded event.

• Declare it inside the function and never reassign it.

• Use a different variable name each time.

• Declare it as a constant.