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MCQOPTIONS
This section includes 302 Mcqs, each offering curated multiple-choice questions to sharpen your Javascript knowledge and support exam preparation. Choose a topic below to get started.
| 101. |
Which event can be fired on any scrollable document element? |
| A. | Window |
| B. | Scroll |
| C. | Load |
| D. | Unload |
| Answer» C. Load | |
| 102. |
Which is the property that is triggered in response to JavaScript errors? |
| A. | onexception |
| B. | onmessage |
| C. | onerror |
| D. | none of the mentioned |
| Answer» D. none of the mentioned | |
| 103. |
The client-side JavaScript’s asynchronous programming model contains |
| A. | Timers and error handlers |
| B. | User interface events |
| C. | State change events |
| D. | API-specific events |
| Answer» B. User interface events | |
| 104. |
The video and the audio belong to the |
| A. | Timers and error handlers |
| B. | API-Specific events |
| C. | State change events |
| D. | User interface events |
| Answer» C. State change events | |
| 105. |
The events that are not directly tied to a specific input device are |
| A. | User interface events |
| B. | Device-independent events |
| C. | Device-dependent events |
| D. | All of the mentioned |
| Answer» C. Device-dependent events | |
| 106. |
The high-level events among the following events are |
| A. | User interface events |
| B. | Device-independent events |
| C. | Device-dependent events |
| D. | All of the mentioned |
| Answer» B. Device-independent events | |
| 107. |
The events that are directly tied to a specific input device are |
| A. | Device-independent input events |
| B. | Device-dependent input events |
| C. | User interface events |
| D. | State change events |
| Answer» C. User interface events | |
| 108. |
In general, event handler is nothing but |
| A. | function |
| B. | interface |
| C. | event |
| D. | handler |
| Answer» B. interface | |
| 109. |
What is the code required to delete all “weight” tags? |
| A. | delete weight(pt).all; |
| B. | delete pt.element[all]; |
| C. | delete pt; |
| D. | delete pt..weight; |
| Answer» E. | |
| 110. |
Which of the following is an example to perform the most common XML manipulations using the XML objects invocation? |
| A. | insertChildBefore() |
| B. | insertChildAfter() |
| C. | appendChildAfter(…) |
| D. | appendChildBefore(…) |
| Answer» B. insertChildAfter() | |
| 111. |
Which of the following is the descendant operator? |
| A. | .. |
| B. | … |
| C. | * |
| D. | @ |
| Answer» C. * | |
| 112. |
Which method to use while working with XML fragments, instead of XML()? |
| A. | XMLInterface() |
| B. | XMLClass() |
| C. | XMLList() |
| D. | XMLArray() |
| Answer» D. XMLArray() | |
| 113. |
What is the return type of typeof for standard JavaScript objects? |
| A. | xml |
| B. | object |
| C. | dom |
| D. | html |
| Answer» C. dom | |
| 114. |
When will the finally block be called? |
| A. | When there is no exception |
| B. | When the catch doesnot match |
| C. | When there is exception |
| D. | None of the mentioned |
| Answer» E. | |
| 115. |
Consider the following code snippet data.sort(function(a,b),b-a); What does the above code do? |
| A. | Sort in the alphabetical order |
| B. | Sort in the chronological order |
| C. | Sort in reverse alphabetical order |
| D. | Sort in reverse numerical order |
| Answer» E. | |
| 116. |
Which method of the iterable object returns an iterator object for the collection? |
| A. | iterator() |
| B. | _iterator_() |
| C. | _iteration_() |
| D. | _return_iterator_() |
| Answer» C. _iteration_() | |
| 117. |
Consider the following code snippet let x=x+1; console.log(x); What will be the result for the above code snippet? |
| A. | 0 |
| B. | Null |
| C. | ReferenceError |
| D. | |
| Answer» E. | |
| 118. |
Consider the following code snippet console.log(p) If p is not defined, what would be the result or type of error? |
| A. | Zero |
| B. | Null |
| C. | ReferenceError |
| D. | ValueNotFoundError |
| Answer» D. ValueNotFoundError | |
| 119. |
Which is the subset that transforms web content into secure modules that can be safely hosted on a web page? |
| A. | Microsoft Web Sandbox |
| B. | ADsafe |
| C. | Caja |
| D. | dojox.secure |
| Answer» E. | |
| 120. |
Why is the this keyword forbidden in JavaScript? |
| A. | Highly memory consuming |
| B. | Functions should access the global objects |
| C. | Functions should not access the global objects |
| D. | Very inefficient to use |
| Answer» D. Very inefficient to use | |
| 121. |
Why was “The Good Parts” designed as a language subset in JavaScript? |
| A. | To improve programmer flexibility |
| B. | To balance the work load of the programmer |
| C. | To create an in-built compiler and interpreter |
| D. | To improve programmer productivity |
| Answer» E. | |
| 122. |
Why does JavaScript subset disallow == and !=? |
| A. | It uses bitwise checking |
| B. | It uses === and !== instead |
| C. | It uses equals() and notequals() instead |
| D. | None of the mentioned |
| Answer» C. It uses equals() and notequals() instead | |
| 123. |
The Crockford’s subset doesnot include which function in JavaScript? |
| A. | eval() |
| B. | coeval() |
| C. | equal() |
| D. | equivalent() |
| Answer» B. coeval() | |
| 124. |
What would be the result of the following statement in JavaScript using regular expression methods ? |
| A. | Returns [“123″”456″”789”] |
| B. | Returns [“123″,”456″,”789”] |
| C. | Returns [1,2,3,4,5,6,7,8,9] |
| D. | Throws an exception |
| Answer» C. Returns [1,2,3,4,5,6,7,8,9] | |
| 125. |
The method that performs the search-and-replace operation to strings for pattern matching is |
| A. | searchandreplace() |
| B. | add() |
| C. | edit() |
| D. | replace() |
| Answer» C. edit() | |
| 126. |
What does the subexpression /java(script)?/ result in ? |
| A. | It matches “java” followed by the optional “script” |
| B. | It matches “java” followed by any number of “script” |
| C. | It matches “java” followed by a minimum of one “script” |
| D. | None of the mentioned |
| Answer» B. It matches “java” followed by any number of “script” | |
| 127. |
What will be the result when non greedy repetition is used on the pattern /a+?b/ ? |
| A. | Matches the letter b preceded by the fewest number of a’s possible |
| B. | Matches the letter b preceded by any number of a |
| C. | Matches letter a preceded by letter b, in the stack order |
| D. | None of the mentioned |
| Answer» B. Matches the letter b preceded by any number of a | |
| 128. |
What does /[^(]* regular expression indicate ? |
| A. | Match one or more characters that are not open paranthesis |
| B. | Match zero or more characters that are open paranthesis |
| C. | Match zero or more characters that are not open paranthesis |
| D. | Match one or more characters that are open paranthesis |
| Answer» D. Match one or more characters that are open paranthesis | |
| 129. |
The regular expression to match any one character not between the brackets is |
| A. | […] |
| B. | [^] |
| C. | [^…] |
| D. | [D] |
| Answer» D. [D] | |
| 130. |
Consider the following statement containing regular expressions var text = "testing: 1, 2, 3"; var pattern = /d+/g; In order to check if the pattern matches, the statement is |
| A. | text==pattern |
| B. | text.equals(pattern) |
| C. | text.test(pattern) |
| D. | pattern.test(text) |
| Answer» E. | |
| 131. |
The ‘$’ present in the RegExp object is called a |
| A. | character |
| B. | matcher |
| C. | metacharacter |
| D. | metadata |
| Answer» D. metadata | |
| 132. |
What can be done in order to avoid creation of global variables in JavaScript? |
| A. | To use a method that defines all the variables |
| B. | To use an object that has the reference to all the variables |
| C. | To use an object as its namespace |
| D. | To use global functions |
| Answer» D. To use global functions | |
| 133. |
The properties() method is a |
| A. | Enumerable method |
| B. | Non-enumerable method |
| C. | Operational method |
| D. | None of the mentioned |
| Answer» C. Operational method | |
| 134. |
Consider the following code snippet var sets = com.davidflanagan.collections.sets; What is the programmer trying to do in the above code snippet? |
| A. | Importing a single module |
| B. | Importing a module partially |
| C. | Importing a namespace |
| D. | Importing the entire module |
| Answer» E. | |
| 135. |
Modules that have more than one item in their API can |
| A. | Assign itself to a global variable |
| B. | Invoke another module of the same kind |
| C. | Return a namespace object |
| D. | Invoke another module of the same kind |
| Answer» D. Invoke another module of the same kind | |
| 136. |
The scope of a function is also called as |
| A. | The function’s scope |
| B. | Module function |
| C. | Modulated function |
| D. | Private function |
| Answer» C. Modulated function | |
| 137. |
Consider the following statement var Set = sets.Set; var s = new Set(1,2,3); What could be the efficiency quotient of the above two statements ? |
| A. | The programmer imports at once the frequently used values into the global namespace |
| B. | There is no efficiency quotient, the programmer tries to make it inefficient |
| C. | The programmer needs to import the Sets everytime he wants to use it |
| D. | All of the mentioned |
| Answer» B. There is no efficiency quotient, the programmer tries to make it inefficient | |
| 138. |
To define each of the set classes as a property of the sets object (namespace) for the module, the statement is |
| A. | sets = sets.AbstractEnumerableSet.extend(); |
| B. | sets.SingletonSet = sets.AbstractEnumerableSet.extend(...); |
| C. | sets.SingletonSet = sets.extend(...); |
| D. | sets = sets.extend(...); |
| Answer» C. sets.SingletonSet = sets.extend(...); | |
| 139. |
The functions provide() and require() of Dojo toolkit and Google’s Closure library are used for |
| A. | declaring and loading modules |
| B. | loading and declaring modules |
| C. | declaring modules |
| D. | none of the mentioned |
| Answer» B. loading and declaring modules | |
| 140. |
You can refresh the webpage in JavaScript by using |
| A. | window.reload |
| B. | location.reload |
| C. | window.refresh |
| D. | page.refresh |
| Answer» C. window.refresh | |
| 141. |
What is the procedure to add methods to HTMLElement so that they will be inherited by the objects that represent the HTML tags in the current document? |
| A. | HTMLElement.prototype(…) |
| B. | HTMLElement.prototype |
| C. | HTML.addmethods() |
| D. | HTML.elements(add) |
| Answer» C. HTML.addmethods() | |
| 142. |
How can we make methods available on all objects? |
| A. | Object.add(methods) |
| B. | Object.methods(add) |
| C. | Object.add.methods(…) |
| D. | Object.prototype |
| Answer» E. | |
| 143. |
The class that represents the regular expressions is |
| A. | RegExpObj |
| B. | RegExpClass |
| C. | RegExp |
| D. | StringExp |
| Answer» D. StringExp | |
| 144. |
Which are usually variables that are used internally in object methods and also are globally visible variables? |
| A. | Object properties |
| B. | Variable properties |
| C. | Method properties |
| D. | Internal properties |
| Answer» C. Method properties | |
| 145. |
The properties of the objects act like different kinds of class members. They are |
| A. | Public object, Private object, Protected object |
| B. | Constructor object, Function object, Destructor object |
| C. | Constructor object, Prototype object, Instance object |
| D. | Instance method, Static object, Dynamic object |
| Answer» D. Instance method, Static object, Dynamic object | |
| 146. |
The method that can be used to create new properties and also to modify the attributes of existing properties is |
| A. | Object.defineProperty() |
| B. | Object.defineProperties() |
| C. | Both Object.defineProperty() and Object.defineProperties() |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 147. |
The snippet that filters the filtered set is |
| A. | var t=new FilteredSet(s, {function(s) {return !(x instanceof Set);}); |
| B. | var t=new FilteredSet{function(s) {return !(x instanceof Set);}); |
| C. | var t=new FilteredSet(s, {function(s) {return (x instanceof Set);}); |
| D. | var t=new FilteredSet(s, {function(s) {return x;}); |
| Answer» B. var t=new FilteredSet{function(s) {return !(x instanceof Set);}); | |
| 148. |
If A is the superclass and B is the subclass, then subclass inherting the superclass can be represented as |
| A. | B=inherit(A); |
| B. | B=A.inherit(); |
| C. | B.prototype=inherit(A); |
| D. | B.prototype=inherit(A.prototype); |
| Answer» D. B.prototype=inherit(A.prototype); | |
| 149. |
When a class B can extend another class A, we say that |
| A. | A is the superclass and B is the subclass |
| B. | B is the superclass and A is the subclass |
| C. | Both A and B are the superclass |
| D. | Both A and B are the subclass |
| Answer» B. B is the superclass and A is the subclass | |
| 150. |
The meaning for Augmenting classes is that |
| A. | objects inherit prototype properties even in dynamic state |
| B. | objects inherit prototype properties only in dynamic state |
| C. | objects inherit prototype properties in static state |
| D. | None of the mentioned |
| Answer» B. objects inherit prototype properties only in dynamic state | |