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MCQOPTIONS
This section includes 52 Mcqs, each offering curated multiple-choice questions to sharpen your Javascript knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Consider the following code snippet :var scope = "global scope";function checkscope() {var scope = "local scope";function f(){return scope;}return f;What is the function of the above code snippet? |
| A. | eturns value null |
| B. | eturns exception |
| C. | eturns the value in scope |
| D. | one of the mentioned |
| Answer» D. one of the mentioned | |
| 2. |
Consider the following code snippetfunction hypotenuse(a, b){function square(x){return x*x;}return Math.sqrt(square(a) + square(b));}What does the above code result? |
| A. | um of square of a and b |
| B. | quare of sum of a and b |
| C. | um of a and b square |
| D. | one of the mentioned |
| Answer» B. quare of sum of a and b | |
| 3. |
Consider the following code snippetfunction printprops(o){for(var p in o)console.log(p + ": " + o[p] + "n");}What will the above code snippet result ? |
| A. | rints the contents of each property of o |
| B. | eturns undefined |
| C. | ll of the mentioned |
| D. | one of the mentioned |
| Answer» C. ll of the mentioned | |
| 4. |
Consider the following code snippetvar a1 = [,,,];var a2 = new Array(3);">0 in a10 in a2The result would be |
| A. | rue false |
| B. | alse true |
| C. | rue true |
| D. | alse true |
| Answer» B. alse true | |
| 5. |
Which of the algorithmic languages is lexical scoping standardized in?%! |
| A. | Ada |
| B. | Pascal |
| C. | Modula2 |
| D. | All of the mentioned |
| Answer» E. | |
| 6. |
What is the purpose of the dynamic scoping?%! |
| A. | Variables can be declared outside the scope |
| B. | Variables must be declared outside the scope |
| C. | Variables cannot be declared outside the scope |
| D. | None of the mentioned |
| Answer» B. Variables must be declared outside the scope | |
| 7. |
What is the opposite approach to the lexical scoping?%! |
| A. | Literal scoping |
| B. | Static scoping |
| C. | Dynamic scoping |
| D. | Generic scoping |
| Answer» D. Generic scoping | |
| 8. |
What will happen if reverse() and join() methods are used simultaneously ?%! |
| A. | Reverses and stores in the same array |
| B. | Reverses and concatenates the elements of the array |
| C. | Reverses |
| D. | All of the mentioned |
| Answer» B. Reverses and concatenates the elements of the array | |
| 9. |
The method or operator used to identify the array is%! |
| A. | isarrayType() |
| B. | == |
| C. | === |
| D. | typeof |
| Answer» E. | |
| 10. |
What will happen if a return statement does not have an associated expression?%! |
| A. | It returns the value 0 |
| B. | It will throw an exception |
| C. | It returns the undefined value |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 11. |
Consider the following code snippet :var grand_Total=eval("10*10+5");The output for the above statement would be :%! |
| A. | 10*10+5 |
| B. | 105 as a string |
| C. | 105 as an integer value |
| D. | Exception is thrown |
| Answer» D. Exception is thrown | |
| 12. |
For the below mentioned code snippet:var o = new Object();The equivalent statement is:%! |
| A. | var o = Object(); |
| B. | var o; |
| C. | var o= new Object; |
| D. | Object o=new Object(); |
| Answer» D. Object o=new Object(); | |
| 13. |
What must be done in order to implement Lexical Scoping?%! |
| A. | Get the object |
| B. | Dereference the current scope chain |
| C. | Reference the current scope chain |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 14. |
What is the fundamental rule of lexical scoping?%! |
| A. | Functions are declared in the scope |
| B. | Functions are executed using scope chain |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 15. |
*$_The method or operator used to identify the array is? |
| A. | isarrayType() |
| B. | == |
| C. | === |
| D. | typeof |
| Answer» E. | |
| 16. |
*$_What will happen if a return statement does not have an associated expression?? |
| A. | It returns the value 0 |
| B. | It will throw an exception |
| C. | It returns the undefined value |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 17. |
*$_What must be done in order to implement Lexical Scoping?? |
| A. | Get the object |
| B. | Dereference the current scope chain |
| C. | Reference the current scope chain |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 18. |
*$_What is the fundamental rule of lexical scoping?? |
| A. | Functions are declared in the scope |
| B. | Functions are executed using scope chain |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 19. |
*$_Consider the following code snippet :var grand_Total=eval("10*10+5");The output for the above statement would be :? |
| A. | 10*10+5 |
| B. | 105 as a string |
| C. | 105 as an integer value |
| D. | Exception is thrown |
| Answer» D. Exception is thrown | |
| 20. |
*$_For the below mentioned code snippet:var o = new Object();The equivalent statement is:? |
| A. | var o = Object(); |
| B. | var o; |
| C. | var o= new Object; |
| D. | Object o=new Object(); |
| Answer» D. Object o=new Object(); | |
| 21. |
*/*_What will happen if reverse() and join() methods are used simultaneously ?? |
| A. | Reverses and stores in the same array |
| B. | Reverses and concatenates the elements of the array |
| C. | Reverses |
| D. | All of the mentioned |
| Answer» B. Reverses and concatenates the elements of the array | |
| 22. |
_ The reduce and reduceRight methods follow a common operation called$? |
| A. | filter and fold |
| B. | inject and fold |
| C. | finger and fold |
| D. | fold |
| Answer» C. finger and fold | |
| 23. |
_ What is the purpose of a return statement in a function?$? |
| A. | Returns the value and continues executing rest of the statements, if any |
| B. | Returns the value and stops the program |
| C. | Returns the value and stops executing the function |
| D. | Stops executing the function and returns the value |
| Answer» E. | |
| 24. |
_ What kind of scoping does JavaScript use?$? |
| A. | Literal |
| B. | Lexical |
| C. | Segmental |
| D. | Sequential |
| Answer» C. Segmental | |
| 25. |
_ Consider the following code snippet :var scope = "global scope";function checkscope() {var scope = "local scope"; function f() { return scope; }return f;What is the function of the above code snippet?$? |
| A. | Returns value null |
| B. | Returns exception |
| C. | Returns the value in scope |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 26. |
_ Which is an equivalent code to invoke a function m of class o that expects two arguments x and y?$? |
| A. | o(x,y); |
| B. | o.m(x) && o.m(y); |
| C. | m(x,y); |
| D. | o.m(x,y); |
| Answer» E. | |
| 27. |
_ If you have a function f and an object o, you can define a method named m of o with$? |
| A. | o.m=m.f; |
| B. | o.m=f; |
| C. | o=f.m; |
| D. | o=f; |
| Answer» B. o.m=f; | |
| 28. |
_ Consider the following code snippet :if (!a[i]) continue ;What is the observation made ?$? |
| A. | Skips the undefined elements |
| B. | Skips the non existent elements |
| C. | Skips the null elements |
| D. | All of the mentioned |
| Answer» E. | |
| 29. |
_The primary purpose of the array map() function is that it$? |
| A. | maps the elements of another array into itself |
| B. | passes each element of the array and returns the necessary mapped elements |
| C. | passes each element of the array on which it is invoked to the function you specify, and returns an array containing the values returned by that function |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 30. |
_When does the function name become optional in JavaScript?$? |
| A. | When the function is defined as a looping statement |
| B. | When the function is defined as expressions |
| C. | When the function is predefined |
| D. | All of the mentioned |
| Answer» C. When the function is predefined | |
| 31. |
_Consider the following code snippet :var c = counter(), d = counter(); function constfuncs() { var funcs = []; for(var i = 0; i < 10; i++) funcs[i] = function() { return i; }; return funcs;}var funcs = constfuncs();funcs[5]()What does the last statement return ?$? |
| A. | 9 |
| B. | 0 |
| C. | 10 |
| D. | None of the mentioned |
| Answer» D. None of the mentioned | |
| 32. |
_Which of the following uses a lot of CPU cycles?$? |
| A. | GUI |
| B. | Statically generated graphics |
| C. | Dynamically generated graphics |
| D. | All of the mentioned |
| Answer» D. All of the mentioned | |
| 33. |
_Which of the following is the correct code for invoking a function without this keyword at all, and also too determine whether the strict mode is in effect?$? |
| A. | var strict = (function { return this; }); |
| B. | mode strict = (function() { return !this; }()); |
| C. | var strict = (function() { return !this; }()); |
| D. | mode strict = (function { }); |
| Answer» D. mode strict = (function { }); | |
| 34. |
_Consider the following code snippet :var string2Num=parseInt("123xyz");The result for the above code snippet would be :$? |
| A. | 123 |
| B. | 123xyz |
| C. | Exception |
| D. | NaN |
| Answer» C. Exception | |
| 35. |
_The pop() method of the array does which of the following task ?$? |
| A. | decrements the total length by 1 |
| B. | increments the total length by 1 |
| C. | prints the first element but no effect on the length |
| D. | None of the mentioned |
| Answer» B. increments the total length by 1 | |
| 36. |
Consider the following code snippet :var a = []; a.unshift(1); a.unshift(22);a.shift(); a.unshift(3,[4,5]); a.shift(); a.shift();a.shift();The final output for the shift() is$? |
| A. | 1 |
| B. | [4,5] |
| C. | [3,4,5] |
| D. | Exception is thrown |
| Answer» B. [4,5] | |
| 37. |
Consider the following code snippetfunction printprops(o) { for(var p in o) console.log(p + ": " + o[p] + "n");}What will the above code snippet result ?$? |
| A. | Prints the contents of each property of o |
| B. | Returns undefined |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 38. |
Consider the following code snippetfunction hypotenuse(a, b) { function square(x) { return x*x; } return Math.sqrt(square(a) + square(b));}What does the above code result?$? |
| A. | Sum of square of a and b |
| B. | Square of sum of a and b |
| C. | Sum of a and b square |
| D. | None of the mentioned |
| Answer» B. Square of sum of a and b | |
| 39. |
Consider the following code snippet :var tensquared = (function(x) {return x*x;}(10));Will the above code work ?$? |
| A. | Yes, perfectly |
| B. | Error |
| C. | Exception will be thrown |
| D. | Memory leak |
| Answer» B. Error | |
| 40. |
Consider the following code snippet :var c = counter(), d = counter(); c.count()d.count() c.reset() c.count() d.count()The state stored in d is :$? |
| A. | 1 |
| B. | 0 |
| C. | Null |
| D. | Undefined |
| Answer» B. 0 | |
| 41. |
Which of the following are examples of closures?$? |
| A. | Objects |
| B. | Variables |
| C. | Functions |
| D. | All of the mentioned |
| Answer» E. | |
| 42. |
Consider the following code snippet :var a = []; a.unshift(1); a.unshift(22);a.shift(); a.unshift(3,[4,5]); a.shift(); a.shift();a.shift();The final output for the shift() is? |
| A. | 1 |
| B. | [4,5] |
| C. | [3,4,5] |
| D. | Exception is thrown |
| Answer» B. [4,5] | |
| 43. |
Consider the following code snippetfunction printprops(o) { for(var p in o) console.log(p + ": " + o[p] + "n");}What will the above code snippet result ?? |
| A. | Prints the contents of each property of o |
| B. | Returns undefined |
| C. | All of the mentioned |
| D. | None of the mentioned |
| Answer» C. All of the mentioned | |
| 44. |
Consider the following code snippet :var c = counter(), d = counter(); c.count()d.count() c.reset() c.count() d.count()The state stored in d is :? |
| A. | 1 |
| B. | 0 |
| C. | Null |
| D. | Undefined |
| Answer» B. 0 | |
| 45. |
Which of the following are examples of closures?? |
| A. | Objects |
| B. | Variables |
| C. | Functions |
| D. | All of the mentioned |
| Answer» E. | |
| 46. |
Consider the following code snippetfunction hypotenuse(a, b) { function square(x) { return x*x; } return Math.sqrt(square(a) + square(b));}What does the above code result?? |
| A. | Sum of square of a and b |
| B. | Square of sum of a and b |
| C. | Sum of a and b square |
| D. | None of the mentioned |
| Answer» B. Square of sum of a and b | |
| 47. |
Consider the following code snippet :var tensquared = (function(x) {return x*x;}(10));Will the above code work ?? |
| A. | Yes, perfectly |
| B. | Error |
| C. | Exception will be thrown |
| D. | Memory leak |
| Answer» B. Error | |
| 48. |
Consider the following code snippetvar a1 = [,,,]; var a2 = new Array(3); ">0 in a1 0 in a2The result would be |
| A. | true false |
| B. | false true |
| C. | true true |
| D. | false true |
| Answer» B. false true | |
| 49. |
Consider the following code snippet :var a = [1,2,3,4,5];a.slice(0,3);What is the possible output for the above code snippet ? |
| A. | Returns [1,2,3] |
| B. | Returns [4,5] |
| C. | Returns [1,2,3,4] |
| D. | Returns [1,2,3,4,5] |
| Answer» B. Returns [4,5] | |
| 50. |
What is the difference between the two lines given below ?!!(obj1 && obj2);(obj1 && obj2); |
| A. | Both the lines result in a boolean value “True” |
| B. | Both the lines result in a boolean value “False” |
| C. | Both the lines checks just for the existence of the object alone |
| D. | The first line results in a real boolean value whereas the second line merely checks for the existence of the objects |
| Answer» E. | |