JavaScript MCQ Questions with answers and solutions Page 1

B

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Q. The development environment offers which standard construct for data validation

(A) Super controlled loop constructs
(B) Case sensitivity check
(C) Validation constructs
(D) All of the mentioned

💬 Discuss

✅ Correct Answer: (D) All of the mentioned

Explanation:

A development environment provides multiple standard constructs for data validation, including:

Super controlled loop constructs – Used to iterate over inputs and validate them efficiently.
Case sensitivity check – Ensures data consistency by validating case-sensitive inputs (e.g., username, passwords).
Validation constructs – Includes built-in validation tools like regex, required fields, and type checks.

Since all these contribute to data validation, option (D) All of the mentioned is correct.

B

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📊 JavaScript

Q. The main purpose of a “Live Wire” in NetScape is to

(A) Create linkage between client side and server side
(B) Permit server side, JavaScript code, to connect to RDBMS
(C) Support only non relational database
(D) To interpret JavaScript code

💬 Discuss

✅ Correct Answer: (B) Permit server side, JavaScript code, to connect to RDBMS

Explanation:

LiveWire was a server-side JavaScript framework introduced by Netscape in the 1990s. It allowed developers to write server-side scripts in JavaScript, enabling interaction with relational databases (RDBMS) like Oracle and Sybase.

Other options are incorrect because:

(A) Create linkage between client-side and server-side → Not its main function, though it facilitated server-side scripting.
(C) Support only non-relational database → Incorrect, as it worked with relational databases.
(D) To interpret JavaScript code → JavaScript engines interpret JS, not LiveWire specifically.

B

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📊 JavaScript

Q. The script tag must be placed in

(A) head
(B) head and body
(C) title and head
(D) all of the mentioned

💬 Discuss

✅ Correct Answer: (B) head and body

Explanation:

In HTML, the <script> tag can be placed in both the <head> and <body> sections:

In the <head> section:

If the script is needed before the page loads (e.g., setting up configurations or defining functions).
Example:

In the <body> section:

Commonly used for scripts that interact with page elements to ensure the document is fully loaded.
Example:

In both <head> and <body>:

A mix of both can be used depending on the script’s purpose.

Incorrect options:

(C) title and head → <script> is not allowed inside <title>.
(D) all of the mentioned → Since <script> is not valid inside <title>, this option is incorrect.

<body>

    <script>

        console.log("Script in body");

    </script>

</body>

<head>

    <script>

        console.log("Script in head");

    </script>

</head>

B

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Q. A JavaScript program developed on a Unix Machine

(A) will throw errors and exceptions
(B) must be restricted to a Unix Machine only
(C) will work perfectly well on a Windows Machine
(D) will be displayed as a JavaScript text on the browser

💬 Discuss

✅ Correct Answer: (C) will work perfectly well on a Windows Machine

Explanation:

JavaScript is a platform-independent and interpreted language, meaning that as long as the browser supports JavaScript, the script will work on any operating system (Unix, Windows, macOS, etc.).

Why the other options are incorrect:

(A) will throw errors and exceptions → JavaScript does not depend on the OS, so it won’t throw errors just because it's developed on Unix.
(B) must be restricted to a Unix Machine only → JavaScript is not OS-dependent, so it can run on any machine with a browser.
(D) will be displayed as a JavaScript text on the browser → If the browser supports JavaScript (which almost all modern browsers do), it will execute the script instead of displaying it as text.

B

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Q. JavaScript is ideal to

(A) make computations in HTML simpler
(B) minimize storage requirements on the web server
(C) increase the download time for the client
(D) none of the mentioned

💬 Discuss

✅ Correct Answer: (B) minimize storage requirements on the web server

Explanation:

JavaScript is a client-side scripting language, meaning that it executes in the user’s browser rather than on the server. This helps:

Reduce server load by handling computations, form validations, and user interactions locally.
Minimize storage requirements on the web server since many tasks can be performed on the client-side without frequent server requests.

Why the other options are incorrect:

(A) make computations in HTML simpler → JavaScript enhances interactivity but does not directly simplify computations in HTML (though it can manipulate HTML dynamically).
(C) increase the download time for the client → JavaScript files are usually lightweight and cached by browsers, so they do not necessarily increase download time.
(D) none of the mentioned → Option (B) is correct, so this is incorrect.

B

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Q. Which attribute is used to specify that the script is executed when the page has finished parsing ( only for external scripts )

(A) parse
(B) a sync
(C) defer
(D) type

💬 Discuss

✅ Correct Answer: (C) defer

Explanation:

The defer attribute ensures that an external script is executed only after the HTML document has been fully parsed. This prevents blocking the rendering process, improving page load performance.

Key Differences Between defer and async:

defer → Scripts execute in order, after the HTML is fully parsed.
async → Scripts execute as soon as they are downloaded, potentially before the HTML is fully parsed.

Why the other options are incorrect:

(A) parse → No such attribute exists in HTML.
(B) async → Executes the script as soon as it is downloaded, not after parsing is complete.
(D) type → Defines the type of script (e.g., "text/javascript"), but doesn’t control execution timing.

B

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📊 JavaScript

Q. JavaScript Code can be called by using

(A) RMI
(B) Triggering Event
(C) Preprocessor
(D) Function/Method

💬 Discuss

✅ Correct Answer: (D) Function/Method

Explanation:

In JavaScript, code execution is typically triggered using functions or methods. Functions are reusable blocks of code that can be called whenever needed.

Why the other options are incorrect:

(A) RMI (Remote Method Invocation) → Used in Java (not JavaScript) for calling methods remotely over a network.
(B) Triggering Event → Events (like onclick, onload) can trigger

B

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📊 JavaScript

Q. JavaScript can be written

(A) directly into JS file and included into HTML
(B) directly on the server page
(C) directly into HTML pages
(D) all of the mentioned

💬 Discuss

✅ Correct Answer: (D) all of the mentioned

Explanation:

JavaScript can be written in multiple ways:

Directly into a .js file and included into an HTML page

Example:

Directly on the server page

JavaScript can be used in server-side environments like Node.js.

Directly into HTML pages using the <script> tag

Example:

Thus, JavaScript supports all these methods, making (D) all of the mentioned the correct answer.

<script>

    alert("Hello, JavaScript!");

</script>

<script src="script.js"></script>

B

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📊 JavaScript

Q. Which of the following Attribute is used to include External JS code inside your HTML Document

(A) src
(B) ext
(C) script
(D) link

💬 Discuss

✅ Correct Answer: (A) src

Explanation:

The src attribute is used to include an external JavaScript file inside an HTML document. It specifies the path to the external .js file.

Example:

<script src="script.js"></script>

Other options:

(B) ext → Incorrect, as there is no ext attribute for including JavaScript.
(C) script → Incorrect, because <script> is an HTML tag, not an attribute.
(D) link → Incorrect, as <link> is used for CSS files, not JavaScript.

Thus, the correct answer is (A) src.

B

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📊 JavaScript

Q. A proper scripting language is a

(A) High level programming language
(B) Assembly level programming language
(C) Machine level programming language
(D) Low level programming language

💬 Discuss

✅ Correct Answer: (A) High level programming language

Explanation:

A scripting language is a high-level programming language designed for automating tasks, controlling software applications, and enhancing functionality. Examples include JavaScript, Python, and Bash.

Other options:

(B) Assembly level programming language → Incorrect, as scripting languages are not written in assembly code.
(C) Machine level programming language → Incorrect, since scripting languages are not directly executed by the CPU without an interpreter.
(D) Low level programming language → Incorrect, because scripting languages are typically abstracted from hardware-specific operations.

Thus, the correct answer is (A) High level programming language.

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