Q
Which of the following is a recommended practice for optimizing JavaScript performance?

Answer & Solution

Answer: Option A
Solution:
Minifying and concatenating scripts reduces file size and HTTP requests, optimizing JavaScript performance. Including all scripts in the <head> can lead to longer page load times, whereas synchronous loading can block rendering and affect performance negatively.
Related Questions on Average

Placing JavaScript at the end of the <body> section is beneficial for:

A). Improving page load speed.

B). Blocking page rendering.

C). Increasing script complexity.

D). Hiding script functionalities.

Variables declared in the <head> section of an HTML document are accessible:

A). Globally throughout the document.

B). Only within the <head> section.

C). Only after the page has fully loaded.

D). Nowhere in the document.

Which scenario is suitable for placing JavaScript in the <head> section of an HTML document?

A). Initializing variables or configurations.

B). Dynamic content manipulation.

C). User interaction scripts.

D). External script loading.

Using the defer attribute with an external JavaScript file in the <body> section means that the script:

A). Loads and executes after HTML parsing.

B). Loads synchronously with HTML parsing.

C). Loads and executes before HTML parsing.

D). Loads but doesn't execute.

Placing JavaScript at the end of the <body> section of an HTML document can result in:

A). Faster initial page rendering.

B). Slower overall page loading.

C). No impact on page performance.

D). Delayed execution of JavaScript.

What happens if JavaScript code in the <head> section of an HTML document is not properly handled?

A). It may block rendering and cause delays.

B). It automatically moves to the <body>.

C). It gets executed twice.

D). It has no impact on the page.

Variables declared in the <body> section of an HTML document have what scope by default?

A). Local to the script or function.

B). Global throughout the document.

C). Limited to the <body> section.

D). Not accessible in JavaScript.

How can JavaScript be loaded asynchronously in the <body> section without blocking page rendering?

A). Using the defer attribute.

B). Using the async attribute.

C). Including scripts in the <head>.

D). Not possible in the <body>.

Which attribute can be used to make external JavaScript files load asynchronously in the <head> or <body> sections?

A). async

B). defer

C). sync

D). load

Placing JavaScript in the <head> section can impact page load times because:

A). It blocks rendering until executed.

B). It loads scripts asynchronously.

C). It reduces HTTP requests.

D). It has no impact on loading.

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