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

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>.

What is the purpose of using the async attribute with an external JavaScript file?

A). To load the script asynchronously.

B). To defer script execution.

C). To block rendering until script loads.

D). To ensure script execution order.

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.

Using the defer attribute with an external script in the <head> 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.

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.

What happens if JavaScript code in the <body> section of an HTML document is placed before critical content such as headings or main paragraphs?

A). It may cause FOUC (Flash of Unstyled Content).

B). It has no effect on page rendering.

C). It improves page load speed.

D). It slows down script execution.

What is the advantage of placing JavaScript at the end of the <body> section for non-critical scripts?

A). Faster initial page rendering.

B). Slower page load overall.

C). Better script execution order.

D). Increased script complexity.

When JavaScript is placed in the <head> section of an HTML document, it can:

A). Execute before page rendering.

B). Execute after page rendering.

C). Block rendering until execution.

D). None of the above.

What is the purpose of using the async attribute with an external JavaScript file in the <head> section?

A). To load and execute the script after HTML parsing.

B). To defer script execution.

C). To block rendering until script loads.

D). To ensure script execution order.

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.