Explore topic-wise MCQs in Javascript.

This section includes 157 Mcqs, each offering curated multiple-choice questions to sharpen your Javascript knowledge and support exam preparation. Choose a topic below to get started.

101.

_What does the NamedNodeMap object represent in the HTML DOM?$?

A. Unordered collection of elements
B. Unordered collection of attributes
C. Unordered collection of nodes
D. All of the mentioned
Answer» E.
Discussion
102.

_What is a closure compiler UI?$?

A. Run time application
B. Web application
C. Standalone application
D. All of the mentioned
Answer» C. Standalone application
Discussion
103.

_During the traversing of the stack when you create a locally scoped variable, where does it go after it goes to the namespace?$?

A. Window
B. Function
C. Document
D. Location
Answer» C. Document
Discussion
104.

_Why shouldn’t JavaScript functions not be too long?$?

A. User friendliness
B. Tie up event loops
C. Browser becomes unresponsive
D. All of the mentioned
Answer» E.
Discussion
105.

_Why is a closure template used?$?

A. Statically updating in JavaScript
B. To increase the efficiency and convenience
C. Dynamically generating HTML in Java and JavaScript
D. All of the mentioned
Answer» D. All of the mentioned
Discussion
106.

_Which API makes the user’s current location available to browser-based application?$?

A. Java API
B. SDL API
C. Object API
D. Geolocation API
Answer» E.
Discussion
107.

_When does one use the event ready?$?

A. Before loading
B. During loading
C. After loading
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
108.

_Which of the following is possible to be referenced in external JavaScript?$?

A. cpp
B. cs
C. php
D. all of the mentioned
Answer» D. all of the mentioned
Discussion
109.

_What is the purpose of the function parameter filetype?$?

A. File type to be expected
B. File type previously got
C. File type that should not be got
D. None of the mentioned
Answer» B. File type previously got
Discussion
110.

_When does a cycle occur during memory leak?$?

A. No reference occurs
B. Two objects reference
C. One object gets referenced
D. One object gets referenced
Answer» C. One object gets referenced
Discussion
111.

_The blobs are generally stored in$?

A. Memory
B. Disk
C. Both Memory and Disk
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
112.

_How can you send data using a Worker object?$?

A. postMessage()
B. sendMessage()
C. Message()
D. post()
Answer» B. sendMessage()
Discussion
113.

_What is the central concept of JavaScript memory management?$?

A. Reliability
B. Reachability
C. Efficiency
D. Transparency
Answer» C. Efficiency
Discussion
114.

_Which of the following is a subtype of Blob?$?

A. Elemental Object
B. Create Object
C. Data Object
D. File Object
Answer» E.
Discussion
115.

What will happen if you reference document.location from within an object?$?

A. Traverses the queue
B. Finds the bugs
C. Traverses the stack
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
116.

Which of the following are static methods in JavaScript?$?

A. Date.parse()
B. Date.UTC()
C. Both Date.parse() and Date.UTC()
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
117.

How do you find the number with the highest value of x and y?$?

A. ceil(x,y)
B. top(x,y)
C. Math.ceil(x,y)
D. Math.max(x,y)
Answer» E.
Discussion
118.

Which class provides an interface for invoking JavaScript methods and examining JavaScript properties?$?

A. ScriptObject
B. JSObject
C. JavaObject
D. Jobject
Answer» C. JavaObject
Discussion
119.

How do we debug a script?$?

A. Use of JavaScript Validator
B. Use of JavaScript Debugger
C. Use of JavaScript Validator & Debugger
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
120.

Where is the error icon option available?$?

A. Tools
B. Help
C. File
D. Edit
Answer» B. Help
Discussion
121.

Which of the following are the properties of a plug-in entry?$?

A. name
B. filename
C. mimeTypes
D. all of the mentioned
Answer» E.
Discussion
122.

What is the purpose of data format validation?$?

A. Data correctness
B. Mere data existence
C. Both Data correctness and Mere data existence
D. None of the mentioned
Answer» B. Mere data existence
Discussion
123.

What is the purpose of the Legacy DOM ?$?

A. Makes the scripting easier
B. Allows access to few keys and elements
C. All of the mentioned
D. None of the mentioned
Answer» C. All of the mentioned
Discussion
124.

What is the purpose of the simple mode?$?

A. Removes whitespaces
B. Does not remove white spaces
C. Removes the unwanted words
D. None of the mentioned
Answer» B. Does not remove white spaces
Discussion
125.

What is the purpose of the advanced mode in the closure compiler?$?

A. Renames variables
B. Renames function
C. Both Renames variables and function
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
126.

Which of the following functions are synchronous?$?

A. load()
B. require()
C. both load() and require()
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
127.

What will happen if you specify an absolute URL in the Worker constructor?$?

A. Resolves itself
B. Must have the same origin
C. Must not have the same origin
D. None of the mentioned
Answer» C. Must not have the same origin
Discussion
128.

The size of blobs are generally calculated in$?

A. Meters
B. Kilometers
C. Bytes
D. Pixels
Answer» D. Pixels
Discussion
129.

Which object can be used to create your own blobs?$?

A. Creator
B. BlobCreator
C. BlobBuilder
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
130.

Which handler is triggered when the content of the document in the window is stable and ready for manipulation?$?

A. onload
B. manipulate
C. create
D. none of the mentioned
Answer» B. manipulate
Discussion
131.

What is the purpose of destroying the functions and objects?$?

A. Consume unnecessary CPU cycles
B. Prevent the dropping of reference count to 0
C. Centralize the responsibility to clean up
D. All of the mentioned
Answer» E.
Discussion
132.

Which of the following is added to prefs.js when the console is automatically opened during JavaScript error?$?

A. user_pref("javascript.console.open_on_error", true);
B. user_pref("javascript.console.open_error ", true);
C. user_pref("javascript.console.open_error ", false);
D. user_pref(" javascript.console.open_on_error", false);
Answer» B. user_pref("javascript.console.open_error ", true);
Discussion
133.

How is everything treated in HTML DOM?$?

A. Node
B. Attributes
C. Elements
D. All of the mentioned
Answer» B. Attributes
Discussion
134.

What is the purpose of the RegExp method test()?$?

A. Tests for a match in its float parameter
B. Tests for a match in its string parameter
C. Tests for a match in its integer parameter
D. None of the mentioned
Answer» C. Tests for a match in its integer parameter
Discussion
135.

What is the purpose of XMLHttpRequest?$?

A. Multiple loading
B. Load content by loading new document
C. Load content without loading new document
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
136.

What is the purpose of the event disconnectionEvent?$?

A. Player demands for disconnection
B. Player disconnects from the channel
C. There is no user interaction
D. None of the mentioned
Answer» C. There is no user interaction
Discussion
137.

How is everything treated in HTML DOM??

A. Node
B. Attributes
C. Elements
D. All of the mentioned
Answer» B. Attributes
Discussion
138.

What is the purpose of the simple mode??

A. Removes whitespaces
B. Does not remove white spaces
C. Removes the unwanted words
D. None of the mentioned
Answer» B. Does not remove white spaces
Discussion
139.

During the traversing through the stack, where does it go after it goes to the window??

A. Namespace
B. Function
C. Document
D. None of the mentioned
Answer» E.
Discussion
140.

Which of the following functions are synchronous??

A. load()
B. require()
C. both load() and require()
D. none of the mentioned
Answer» D. none of the mentioned
Discussion
141.

What is the purpose of the advanced mode in the closure compiler??

A. Renames variables
B. Renames function
C. Both Renames variables and function
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
142.

What is the purpose of XMLHttpRequest??

A. Multiple loading
B. Load content by loading new document
C. Load content without loading new document
D. None of the mentioned
Answer» D. None of the mentioned
Discussion
143.

What is the purpose of the event disconnectionEvent??

A. Player demands for disconnection
B. Player disconnects from the channel
C. There is no user interaction
D. None of the mentioned
Answer» C. There is no user interaction
Discussion
144.

Which of the following is added to prefs.js when the console is automatically opened during JavaScript error??

A. user_pref("javascript.console.open_on_error", true);
B. user_pref("javascript.console.open_error ", true);
C. user_pref("javascript.console.open_error ", false);
D. user_pref(" javascript.console.open_on_error", false);
Answer» B. user_pref("javascript.console.open_error ", true);
Discussion
145.

What is the purpose of the RegExp method test()??

A. Tests for a match in its float parameter
B. Tests for a match in its string parameter
C. Tests for a match in its integer parameter
D. None of the mentioned
Answer» C. Tests for a match in its integer parameter
Discussion
146.

What is the purpose of destroying the functions and objects??

A. Consume unnecessary CPU cycles
B. Prevent the dropping of reference count to 0
C. Centralize the responsibility to clean up
D. All of the mentioned
Answer» E.
Discussion
147.

The size of blobs are generally calculated in?

A. Meters
B. Kilometers
C. Bytes
D. Pixels
Answer» D. Pixels
Discussion
148.

What will happen if you specify an absolute URL in the Worker constructor??

A. Resolves itself
B. Must have the same origin
C. Must not have the same origin
D. None of the mentioned
Answer» C. Must not have the same origin
Discussion
149.

Which handler is triggered when the content of the document in the window is stable and ready for manipulation??

A. onload
B. manipulate
C. create
D. none of the mentioned
Answer» B. manipulate
Discussion
150.

Which object can be used to create your own blobs??

A. Creator
B. BlobCreator
C. BlobBuilder
D. None of the mentioned
Answer» D. None of the mentioned
Discussion