Q
What does console.log() output when logging an undefined variable?

Answer & Solution

Answer: Option Option B
Solution:
When logging an undefined variable using console.log(), the output will be 'undefined'. This indicates that the variable has not been assigned a value or does not exist in the current scope. It is different from an empty string, null, or an error message, as 'undefined' is a specific value in JavaScript that represents the absence of a value for a variable. Logging undefined variables using console.log() is useful for debugging and identifying variables that need initialization or assignments in the code.
Related Questions on Average

How does console.log() handle logging complex data structures like objects or arrays?

A). It prints the memory address of the data structure.

B). It converts objects and arrays into readable string representations.

C). It displays an error message for complex data structures.

D). It ignores complex data structures and logs a warning.

How can you log multiple values or messages using console.log()?

A). By using separate console.log() statements for each value.

B). By concatenating values within the parentheses.

C). By using HTML tags in the message string.

D). By separating values with commas within the parentheses.

What is the primary purpose of console.log() in JavaScript?

A). To display messages on the webpage.

B). To log information to the browser's console.

C). To prompt user input.

D). To create interactive elements.

How does console.log() affect the performance of a webpage?

A). It improves page loading speed.

B). It has no impact on page performance.

C). It may slightly degrade performance if used excessively.

D). It optimizes JavaScript execution.

Which method can be used to log warning messages in JavaScript?

A). console.debug()

B). console.info()

C). console.warn()

D). console.error()

What type of information can be logged using console.log() in JavaScript?

A). Only strings and text-based data.

B). Strings, numbers, objects, arrays, and other data types.

C). Numbers and mathematical calculations.

D). Images and multimedia content.

How does console.log() handle logging objects with nested properties?

A). It prints only the top-level properties of the object.

B). It converts the object and all nested properties into string representations.

C). It displays an error message for objects with nested properties.

D). It ignores nested properties and logs the object structure only.

How can you include JavaScript expressions in console.log() messages?

A). By enclosing expressions in backticks (`) within the message string.

B). By using special symbols like %s and %d.

C). By wrapping expressions in square brackets [].

D). By assigning expressions to separate log methods.

How can you improve the readability of log messages in console.log()?

A). By including detailed error messages.

B). By using clear and descriptive message content.

C). By logging messages in reverse order.

D). By including HTML tags for styling.

How is console.log() used to display variable values in the console?

A). By concatenating variables with strings.

B). By using special escape characters.

C). By including variables directly in the parentheses.

D). By using HTML tags.