A developer is working on a legacy codebase and finds a section of code that is commented out. The developer needs to understand why it was disabled. Which action is most appropriate?

Check the browser console for errors related to the code.

Delete the commented-out code to clean up the file.

Uncomment the code and test it to see if it works.

Read the comments surrounding the code for an explanation.

A developer is debugging a performance issue and wants to measure how long a function takes to execute. The developer also needs to log the result only if the execution time exceeds a threshold. Which approach should be used?

Use Date.now() before and after the function, then log the difference if it exceeds the threshold.

Use console.profile() to record the function's performance.

Use console.time() and console.timeEnd() around the function, then compare the output manually.

Use console.log() with a timestamp before and after the function.

LPI Web Development Essentials

Domain 4Objective 1

034.1 JavaScript Execution and Syntax (weight: 1) WEB-DEVELOPMENT-ESSENTIALS Practice Questions (Page 1)

Part of the 034 JavaScript Programming domain, which makes up ~16% of our current practice bank. Linux Professional Institute does not publish an official question count, but from its 60-minute exam (~25–40 total, ~4–6 in this domain), expect 1–2 from this objective — we provide 19 practice questions to prepare you well beyond it. (estimate)

19questions here

4free pages

5concepts

Questions 1–5

1application · medium
A developer writes the following code: let a = 10; let b = '5'; console.log(a + b); What will be logged to the console?
Select an answer first
2expert · medium
A developer is working on a legacy codebase and finds a section of code that is commented out. The developer needs to understand why it was disabled. Which action is most appropriate?
Select an answer first
3application · easy
A developer needs to attach a JavaScript function to a button's click event directly in the HTML. Which attribute should be used?
Select an answer first
4expert · hard
A developer is debugging a performance issue and wants to measure how long a function takes to execute. The developer also needs to log the result only if the execution time exceeds a threshold. Which approach should be used?
Select an answer first
5application · easy
A developer wants to see the value of a variable at a specific point in the script's execution. Which method should be used to output it to the console?
Select an answer first

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034.1 JavaScript Execution and Syntax (weight: 1) WEB-DEVELOPMENT-ESSENTIALS Practice Questions (Page 1)

Questions 1–5

A developer writes the following code: let a = 10; let b = '5'; console.log(a + b); What will be logged to the console?

A developer is working on a legacy codebase and finds a section of code that is commented out. The developer needs to understand why it was disabled. Which action is most appropriate?

A developer needs to attach a JavaScript function to a button's click event directly in the HTML. Which attribute should be used?

A developer is debugging a performance issue and wants to measure how long a function takes to execute. The developer also needs to log the result only if the execution time exceeds a threshold. Which approach should be used?

A developer wants to see the value of a variable at a specific point in the script's execution. Which method should be used to output it to the console?

Keep studying — 034 JavaScript Programming