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

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?

A). To load the script asynchronously.

B). To defer script execution.

C). To block rendering until script loads.

D). To ensure script execution order.

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.

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.

Which attribute is used to make an external JavaScript file load and execute after HTML parsing but before the DOMContentLoaded event in the <head> section?

A). async

B). defer

C). sync

D). load

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 should be used for loading external JavaScript files without blocking rendering in the <head> or <body> sections?

A). async

B). defer

C). sync

D). load

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.

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.

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