oDesk Javascript Test Answers 2015
·
1. Which of the following prints
"AbBc"?
Answers:
• var b = 'a'; var result =
b.toUpperCase() + 'b' + 'b'.toUpperCase() +'C'['toLowerCase'](); alert(result);
• var b = 'a';
var result = b.toUpperCase() + 'b' + 'b'.toUpperCase() +'c'['toUpperCase']();
alert(result);
• var b = 'a';
var result = b.toUpperCase() + b + 'b'.toUpperCase() +'C'['toLowerCase']();
alert(result);
• var b = 'a';
var result = b.toUpperCase() + 'b' + 'b'.toUpperCase() +C; alert(result);
2. Performance-wise, which is the
fastest way of repeating a string in JavaScript?
Answers:
•
String.prototype.repeat = function( num ) { return new Array( num + 1 ).join(
this ); }
• function
repeat(pattern, count) { if (count < 1) return ''; var result = ''; while
(count > 0) { if (count & 1) result += pattern; count >>= 1,
pattern += pattern; } return result; }
• String.prototype.repeat =
function(count) { if (count < 1) return ''; var result = '', pattern =
this.valueOf(); while (count > 0) { if (count & 1) result += pattern;
count >>= 1, pattern += pattern; } return result; };
•
String.prototype.repeat = function (n, d) { return --n ? this + (d || '') +
this.repeat(n, d) : '' + this };
3. What is the final value of the
variable bar in the following code?
var foo = 9;
bar = 5;
(function() {
var foo = 2;
bar= 1;
}())
bar = bar + foo;
Answers:
• 10
• 14
• 3
• 7
4. In an HTML page, the form tag is
defined as follows:
<form onsubmit="return
Validate()" action="http://www.mysite.com/">
The validate() function is intended to
prevent the form from being submitted if the name field in the form is empty.
What should the validate() function look like?
Answers:
• <script
type="text/javascript"> function Validate() {
if(document.forms[0].name.value == "") return true; else return
false; } </script>
• <script
type="text/javascript"> function Validate() {
if(document.forms[0].name.value == "") return false; else return
true; } </script>
• script
type="text/javascript"> function Validate() {
if(document.forms[0].name== "") return false; else return true; }
</script>
• <script
type="text/javascript"> function Validate() {
if(document.forms[0].name == "") return true; else return false; }
</script>
5. Which of the following code
snippets changes an image on the page?
Answers:
• var img =
document.getElementById("imageId"); img.src =
"newImage.gif";
• var img =
document.getElementById("imageId"); img.style.src =
"newImage.gif";
• var img =
document.getElementById("imageId"); img.src.value =
"newImage.gif";
• var img =
document.getElementById("imageId"); img = "newImage.gif";
6. Which of the following results is
returned by the JavaScript operator "typeof" for the keyword
"null"?
Answers:
• function
• object
• string
• number
7. Which of the following will check
whether the variable vRast exists or not?
Answers:
• if (typeof
vRast="undefined") {}
• if (typeof vRast
=="undefined") {}
• if
(vRast.defined =true) {}
• if (vRast.defined
==true) {}
8. Which of the following choices will
detect if "variableName" declares a function?
<script>
var variableName= function(){};
</script>
Answers:
• return
variableName;
• nameof
variableName;
• isFunction
variableName;
• typeof variableName;
9. Which of the following choices will
change the source of the image to "image2.gif" when a user clicks on
the image?
Answers:
• img id="imageID"
src="image1.gif" width="50" height="60"
onmousedown="changeimg(image1.gif)" onmouseup="changeimg(image2.gif)"
• img
id="imageID" src="image1.gif" width="50"
height="60" onmouseclick="changeimg(image2.gif)"
onmouseup="changeimg(image1.gif)"
• img
id="imageID" src="image2.gif" width="50"
height="60" onmousedown="changeimg(image1.gif)"
onmouseup="changeimg(image2.gif)"
• img
id="imageID" src="image2.gif" width="50"
height="60" onmousedown="changeimg(image2.gif)"
onmouseup="changeimg(image1.gif)"
• img
id="imageID" src="image1.gif" width="50"
height="60" onmousedown="changeimg('image2.gif')" onmouseup="changeimg('image1.gif')"
10. Which of the following Regular
Expression pattern flags is not valid?
Answers:
• gi
• p
• i
• g
11. Which of the following statements
is correct?
Answers:
• There is no
undefined property in JavaScript.
• Undefined
object properties can be checked using the following code: if (typeof something
== null) alert("something is undefined");
• It is not
possible to check for undefined object properties in JavaScript.
• Undefined object
properties can be checked using the following code: if (typeof something ===
"undefined") alert("something is undefined");
12. Which of the following will change
the color of a paragraph's text to blue when a user hovers over it, and reset
it back to black when the user hovers out?
Answers:
• <p
onmouseover="style.color='black'"
onmouseout="style.color='blue'"> The text of the
paragraph..</p>
• <p
onmouseover="style.color='blue'"
onmouseout="style.color='black'"> The text of the
paragraph..</p>
• <p
onmouseout="style.color='blue'"> The text of the
paragraph..</p>
• <p
onmouseover="style.color='blue'"> The text of the
paragraph..</p>
• <p
onmousein="style.color='blue'"
onmouseout="style.color='black'"> The text of the
paragraph..</p>
13. Which of the following choices
will turn a string into a JavaScript function call (case with objects) of the
following code snippet?
<script>
window.foo = {
bar: {
baz: function() {
alert('Hello!');
}
}
};
</script>
Answers:
• bar['baz']();
•
object['foo']['bar']['baz']();
•
document['foo']['bar']['baz']();
•
window['foo']['bar']['baz']();
14. Which of the following options can
be used for adding direct support for XML to JavaScript?
Answers:
• E4X
• egex
• Generators and
Iterators
• let
15. Which of the following will detect
which DOM element has the focus?
Answers:
• document.activeElement
• document.ready
•
document.referrer
•
document.getelementbyid
16. Which of the following will
randomly choose an element from an array named myStuff, given that the number
of elements changes dynamically?
Answers:
• randomElement =
myStuff[Math.floor(Math.random() * myStuff.length)];
• randomElement =
myStuff[Math.ceil(Math.random() * myStuff.length)];
• randomElement =
myStuff[Math.random(myStuff.length)];
• randomElement =
Math.random(myStuff.length);
17. Which of the following objects in
JavaScript contains the collection called "plugins"?
Answers:
• Location
• Window
• Screen
• Navigator
18. What is the difference between
call() and apply()?
Answers:
• The call() function
accepts an argument list of a function, while the apply() function accepts a
single array of arguments.
• The apply()
function accepts an argument list of a function, while the call() function
accepts a single array of arguments.
• The call()
function accepts an object list of a function, while the apply() function
accepts a single array of an object.
• The call()
function accepts an object list of a function, while the apply() function
accepts a single array of an object.
19. Which of the following code
snippets is more efficient, and why?
<script
language="JavaScript">
for(i=0;i<document.images.length;i++)
document.images[i].src="blank.gif";
</script>
<script
language="JavaScript">
var theimages = document.images;
for(i=0;i<theimages.length;i++)
theimages[i].src="blank.gif"
</script>
Answers:
• Both are equally
efficient.
• The first code
is more efficient as it contains less code.
• The first code
is more efficient as it employs object caching.
• The second code is more
efficient as it employs object caching.
20. Which of the following code
snippets returns "[object object]"?
Answers:
• <script>
var o = new Object(); o.toSource(); </script>
• <script>
var o = new Object(); o.valueOf(); </script>
• <script> var o = new
Object(); o.toString(); </script>
• <script>
var o = new Object(); o.getName(); </script>
21. Select the following function that
shuffles an array?
Answers:
• function shuffle(array) {
var tmp, current, top = array.length; if(top) while(--top) { current =
Math.floor(Math.random() * (top + 1)); tmp = array[current]; array[current] =
array[top]; array[top] = tmp; } return array; }
• function
shuffle(array) { return array.sort(function(a,b) { return (a-b); }); }
• function
shuffle(array) { var results = new Array(); var sorted_arr = array.sort(); for
(var i = 0; i < array.length - 1; i++) { if (sorted_arr[i + 1] ==
sorted_arr[i]) { results.push(sorted_arr[i]); } } return results; }
• function
shuffle(array) { for (var tmp, cur, top=array.length; top--;){ cur =
(Math.random() * (top + 1)) << 0; tmp = array[cur]; array[cur] = array[top];
array[top] = tmp; } return array.sort(); }
22. Which of the following code
snippets removes objects from an associative array?
Answers:
• delete
array["propertyName"];
•
array.propertyName.remove();
•
array.splice(index, 1);
•
array["propertyName"].remove();
23. What is the error in the
statement: var charConvert = toCharCode('x');?
Answers:
• toCharCode() is a
non-existent method.
• Nothing. The
code will work fine.
• toCharCode only
accepts numbers.
• toCharCode
takes no arguments.
24. What does the following JavaScript
code do?
contains(a, obj) {
for (var i = 0; i
< a.length; i++) {
if (a[i] === obj) {
return true;
}
}
return false;
}
Answers:
• It calculates
an array's length.
• It compares 'a'
and 'obj' in an array.
• The code will
cause an error.
• It checks if an array
contains 'obj'.
25. If an image is placed styled with
z-index=-1 and a text paragraph is overlapped with it, which one will be
displayed on top?
Answers:
• The paragraph.
• The image.
• It depends on
other rules.
26. Which of the following code
snippets gets an image's dimensions (height & width) correctly?
Answers:
• var img =
document.getElementById('imageid'); var width = img.clientWidth; var height =
img.clientHeight;
• var img = document.getElementById('imageid');
var width = img.width; var height = img.height;
• var img =
document.getElementById('imageid'); var width = img.getAttribute('width'); var
height = img.getAttribute('height');
• var
img=document.getElementById("imageid"); var width=img.offsetWidth;
var height=img.offsetHeight;
27. The following are the samples for
getting a selected value in the from a dropdown list:
<select
id="ddlViewBy">
<option
value="1">test1</option>
<option value="2"
selected="selected">test2</option>
<option
value="3">test3</option>
</select>
Which code block is correct?
Answers:
• var e =
document.getElementById("ddlViewBy"); var strUser =
e.options[e.selectedIndex].text;
• var e =
document.getElementById("ddlViewBy"); var strUser = e.options[e.selectedIndex].value;
• var e =
document.getElementByName("ddlViewBy"); var strUser =
e.options[e.selectedIndex].text;
• var e =
document.getElementByName("ddlViewBy"); var strUser =
e.options[e.selectedIndex].value;
28. var profits=2489.8237
Which of the following code(s)
produces the following output?
output : 2489.824
Answers:
•
profits.toFixed(4)
• profits.toFixed(3)
•
profits.formatDollar(3)
•
profits.nuberFormat(3)
29. A form contains two fields named
id1 and id2. How can you copy the value of the id2 field to id1?
Answers:
•
document.forms[0].id1.value=document.forms[0].id2.value
•
document.forms[0].id2.value=document.forms[0].id1.value
•
document.id1.value=document.id2.value
•
document.id2.value=document.id1.value
30. Which of the following is true
about setTimeOut()?
Answers:
• The statement(s) it
executes run(s) only once.
• It pauses the
script in which it is called.
• clearTimeOut()
won't stop its execution.
• The delay is
measured in hundredths of a second.
• It is required
in every JavaScript function.
31. How can the operating system of
the client machine be detected?
Answers:
• It is not
possible using JavaScript.
• Using the navigator object
• Using the
window object
• Using the
document object
• None of these.
32. Which of the following
descriptions is true for the code below?
var object0 = {};
Object.defineProperty(object0,
"prop0", { value : 1, enumerable:false, configurable : true });
Object.defineProperty(object0,
"prop1", { value : 2, enumerable:true, configurable : false });
Object.defineProperty(object0,
"prop2", { value : 3 });
object0.prop3 = 4;
Answers:
• Object
'object0' contains 4 properties. Property 'prop2' and property 'prop3' are
available in the for...in loop. Property 'prop0' and property 'prop1' are
available to delete.
• Object
'object0' contains 4 properties. Property 'prop1' and property 'prop2' are
available in the for...in loop. Property 'prop2' and property 'prop3' are
available to delete.
• Object
'object0' contains 4 properties. Property 'prop0' and property 'prop2' are
available in the for...in loop. Property 'prop0' and property 'prop2' are
available to delete.
• Object 'object0' contains
4 properties. Property 'prop1' and property 'prop3' are available in the
for...in loop. Property 'prop0' and property 'prop3' are available to delete.
33. Consider the following variable
declarations:
var a="adam"
var b="eve"
Which of the following would return
the sentence "adam and eve"?
Answers:
•
a.concatinate("and", b)
•
a.concat("and", b)
•
a.concatinate(" and ", b)
• a.concat(" and
", b)
34. Which of the following code
snippets will correctly split "str"?
Answers:
• <script> var str =
'something -- something_else'; var substrn = str.split(' -- '); </script>
• <script>
var str = 'something -- something_else'; var substrn = split.str(' --- ');
</script>
• <script>
var str = 'something -- something_else'; var substrn = str.split(' - ',' - ');
</script>
• <script>
var str = 'something -- something_else'; var substrn = split.str(' - ',' - ');
</script>
35. Which object can be used to
ascertain the protocol of the current URL?
Answers:
• document
• window
• history
• browser
• form
• location
36. Which of the following best
describes a "for" loop?
Answers:
• "for"
loop consists of six optional expressions, enclosed in parentheses and
separated by semicolons, followed by a statement executed in the loop.
• "for"
loop consists of five optional expressions, enclosed in parentheses and
separated by semicolons, followed by a statement executed in the loop.
• "for"
loop consists of four optional expressions, enclosed in parentheses and
separated by semicolons, followed by a statement executed in the loop.
• "for" loop
consists of three optional expressions, enclosed in parentheses and separated
by semicolons, followed by a statement executed in the loop.
37. Which of the following
descriptions best describes the code below?
<script>
var variable1 = { fastFood:
"spaghetti", length: 10 };
Object.freeze(variable1);
variable1.price = 50;
delete variable1.length;
</script>
Answers:
• Object is
frozen, a property named "price" is added in the variable1 object, a
property named "length" is deleted from this object. At the end of
the code, the object "variable1" contains 2 properties.
• Object is
frozen, a property named "price" is not added in the variable1
object, a property named "length" is deleted from this object. At the
end of the code, object "variable1" contains 1 properties.
• Object is
frozen, a property named "price" is added in the variable1 object, a
property named "length" is not deleted from this object. At the end
of the code, object "variable1" contains 1 properties.
• Object is frozen, a property
named "price" is not added in the variable1 object, a property named
"length" is not deleted from this object. At the end of the code,
object "variable1" contains 2 properties.
38. Which of the following is not a
valid HTML event?
Answers:
• ondblclick
• onmousemove
• onclick
• onblink
39. Analyze the following code snippet
which uses a Javascript Regular Expression character set. What will be the
output of this code?
<html>
<body>
<script
type="text/javascript">
var str = "Is
this enough?";
var patt1 = new
RegExp("[^A-J]");
var result =
str.match(patt1);
document.write(result);
</script>
</body>
</html
Answers:
• I
• Is
• s
• I,s,
40. Consider the following image
definition:
<img id="logo"
src="companylogo1.gif" height="12" width="12"
>
Which of the following will change the
image to companylogo2.gif when the page loads?
Answers:
•
logo.source="companylogo2.gif"
•
logo.source="companylogo1.gif"
• document.getElementById('logo').src="companylogo1.gif"
•
document.getElementById('logo').src="companylogo2.gif"
41. Which of the following are
JavaScript unit testing tools?
Answers:
• Buster.js,
jQuery, YUI Yeti
• QUnit,
Modernizr, JsTestDriver
• Node.js,
Modernizr, Jasmine
• Buster.js, YUI Yeti,
Jasmine
42. Which of the following can be used
for disabling the right click event in Internet Explorer?
Answers:
• event.button == 2
• event.button ==
4
• event.click ==
2
• event.click ==
4
43. An image tag is defined as
follows:
<img id="ERImage"
width="100" height="100"
onmouseover="ImageChange()" src="Image1.jpg">
The purpose of the ImageChange()
function is to change the image source to Image2.jpg. Which of the following
should the ImageChange() function look like?
Answers:
•
document.getElementById('ERImage').src="Image1.jpg"
•
document.getElementById('ERImage').src="Image2.jpg"
•
document.getElementById('ERImage').style.src="Image1.jpg"
•
document.getElementById('ERImage').style.src="Image2.jpg"
44. Consider the following JavaScript
alert:
<script
type="text/JavaScript">
function message() {
alert("Welcome
to ExpertRating!!!")
}
</script>
Which of the following will run the
function when a user opens the page?
Answers:
• body
onload="message()"
• body onunload="message()"
• body
onsubmit="message()"
• body
onreset="message()"
45. Which of the following code
snippets will correctly get the length of an object?
Answers:
• <script>
var newObj = new Object(); newObj["firstname"] = "FirstName";
newObj["lastname"] = "LastName"; newObj["age"] =
21; Object.size = function(obj) { var size = 0, key; for (key in obj) { if
(obj.hasOwnProperty(index)) size++; } return size; }; var size = Object.size(newObj);
</script>
• <script>
var newObj = new Object(); newObj["firstname"] =
"FirstName"; newObj["lastname"] = "LastName";
newObj["age"] = 21; Object.size = function(obj) { var size = 0, key;
for (key in obj) { if (obj.hasOwnProperty(value)) size++; } return size; }; var
size = Object.size(newObj); </script>
• <script>
var newObj = new Object(); newObj["firstname"] =
"FirstName"; newObj["lastname"] = "LastName";
newObj["age"] = 21; Object.size = function(obj) { var size = 0, key;
for (key in obj) { if (obj.hasOwnProperty(length)) size++; } return size; };
var size = Object.size(newObj); </script>
• <script> var newObj
= new Object(); newObj["firstname"] = "FirstName";
newObj["lastname"] = "LastName"; newObj["age"] =
21; Object.size = function(obj) { var size = 0, key; for (key in obj) { if (obj.hasOwnProperty(key))
size++; } return size; }; var size = Object.size(newObj); </script>
46. Which of the following Array
methods in JavaScript runs a function on every item in the Array and collects
the result from previous calls, but in reverse?
Answers:
• reduce()
• reduceRight()
• reverse()
• pop()
47. What will be the final value of
the variable "apt"?
var apt=2;
apt=apt<<2;
Answers:
• 2
• 4
• 6
• 8
• 16
48. How can a JavaScript object be
printed?
Answers:
• console.log(obj)
•
console.print(obj)
• console.echo(obj);
• None of these
49. Which of the following is the
correct syntax for using the JavaScript exec() object method?
Answers:
•
RegExpObject.exec()
• RegExpObject.exec(string)
•
RegExpObject.exec(parameter1,parameter2)
• None of these
50. Having an array object var arr =
new Array(), what is the best way to add a new item to the end of an array?
Answers:
• arr.push("New
Item")
• arr[arr.length]
= "New Item"
•
arr.unshift("New Item")
•
arr.append("New Item")
51. Consider the following JavaScript
validation function:
function ValidateField()
{
if(document.forms[0].txtId.value =="")
{return false;}
return true;
}
Which of the following options will
call the function as soon as the user leaves the field?
Answers:
• input
name=txtId type="text" onreset="return ValidateField()"
• input
name=txtId type="text" onfocus="return ValidateField()"
• input
name=txtId type="text" onsubmit="return ValidateField()"
• input name=txtId
type="text" onblur="return ValidateField()"
52. Which of following uses the
"with" statement in JavaScript correctly?
Answers:
• with
(document.getElementById("blah").style) { background =
"black"; color = "blue"; border = "1px solid
green"; }
• with
document.getElementById("blah").style background = "black";
color = "blue"; border = "1px solid green"; End With
• With
document.getElementByName("blah").style background =
"black"; color = "blue"; border = "1px solid
green"; End With
• with
(document.getElementById("blah").style) { .background =
"black"; .color = "blue"; .border = "1px solid
green"; }
53. Consider the following JavaScript
validation function:
<script
type="text/JavaScript">
function ValidateField()
{
if(document.forms[0].txtId.value =="")
{return false;}
return true;
}
</script>
Which of the following options will
call the function as soon as the user leaves the field?
Answers:
• input
name=txtId type="text" onreset="return ValidateField()"
• input
name=txtId type="text" onfocus="return ValidateField()"
• input
name=txtId type="text" onsubmit="return ValidateField()"
• input name=txtId
type="text" onblur="return ValidateField()"
54. Which of the following modifiers
must be set if the JavaScript lastIndex object property was used during pattern
matching?
Answers:
• i
• m
• g
• s
55. Consider the following image
definition:
<img id="logo"
src="companylogo1.gif" height="12" width="12"
>
Which of the following will change the
image to "companylogo2.gif" when the page loads?
Answers:
•
logo.source="companylogo2.gif"
•
logo.source="companylogo1.gif"
•
document.getElementById('logo').src="companylogo1.gif"
•
document.getElementById('logo').src="companylogo2.gif"
56. What would be the use of the
following code?
function validate(field) {
var
valid=''ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'';
var ok=''yes'';
var temp;
for(var
i=0;i<field.value.length;i++) {
temp='''' + field.value.substring(i,i+1)
if(valid.indexOf(temp)==''-1'') {
ok=''no'';
}
}
if(ok==''no'') {
alert(''error'');
field.focus();
}
}
Answers:
• It will force a
user to enter only numeric values.
• It will force a
user to enter only alphanumeric values.
• It will force a user to
enter only English alphabet character values.
• None of these.
57. An image tag is defined as
follows:
<img id="ERImage"
width="100" height="100"
onmouseover="ImageChange()" src="Image1.jpg">
The purpose of the ImageChange()
function is to change the image source to "Image2.jpg". Which of the
following should the ImageChange() function look like?
Answers:
•
document.getElementById('ERImage').src="Image1.jpg"
•
document.getElementById('ERImage').src="Image2.jpg"
•
document.getElementById('ERImage').style.src="Image1.jpg"
•
document.getElementById('ERImage').style.src="Image2.jpg"
58. How can created cookies be deleted
using JavaScript?
Answers:
• They can't be
deleted. They are valid until they expire.
• Overwrite with an expiry
date in the past
• Use escape() on
the value of the path attribute
• Use unescape() on
the value of the path attribute
• The cookie file
will have to be removed from the client machine.
• Wait till the
expiry date is reached
59. What would be the value of 'ind'
after execution of the following code?
var msg="Welcome to
ExpertRating"
var ind= msg.substr(3, 3)
Answers:
• lco
• com
• ome
• Welcome
60. Are the two statements below
interchangeable?
object.property
object[''property'']
Answers:
• Yes
• No
61. Which of the following is not a
valid method in generator-iterator objects in JavaScript?
Answers:
• send()
• throw()
• next()
• stop()
62. Which of the following code
snippets will return all HTTP headers?
Answers:
• var req = new
XMLHttpRequest(); req.open('GET', document.location, false); req.send(null);
var headers = req.getAllResponseHeaders().toLowerCase(); alert(headers);
• var req = new
XMLHttpAccess(); req.open('GET', document.location, false); req.send(null); var
headers = req.getAllResponseHeaders().toLowerCase(); alert(headers);
• var req = new
XMLHttpRequest(); req.open('GET', document.location, false); req.send(null);
var headers = req.getResponseHeader().toLowerCase(); alert(headers);
• var req = new
XMLHttpRequestHeader(); req.open('GET', document.location, false);
req.send(null); var headers = req.retrieveAllResponseHeaders().toLowerCase();
alert(headers);
63. Consider the following JavaScript
alert:
<script
type="text/JavaScript">
function message() {
alert("Welcome
to ExpertRating!!!")
}
</script>
Which of the following will run the
function when a user opens the page?
Answers:
• body
onload="message()"
• body
onunload="message()"
• body
onsubmit="message()"
• body
onreset="message()"
64. Which of the following is the most
secure and efficient way of declaring an array?
Answers:
• var a = []
• var a = new
Array()
• var a = new
Array(n)
• var a
65. Which of the following built-in
functions is used to access form elements using their IDs?
Answers:
• getItem(id)
•
getFormElement(id)
• getElementById(id)
• All of these
66. Which of the following correctly
uses a timer with a function named rearrange()?
Answers:
•
tmr=setTimeout("rearrange ()",1)
•
tmr=Timer(1,"rearrange ()")
•
tmr=Timer("rearrange ()",1)
•
tmr=setTimeout(1,"rearrange ()")
67. Which of the following can be used
to escape the ' character?
Answers:
• *
• \
• -
• @
• #
• %
• |
• ~
68. Which event can be used to
validate the value in a field as soon as the user moves out of the field by
pressing the tab key?
Answers:
• onblur
• onfocus
• lostfocus
• gotfocus
• None of these
69. When setting cookies with
JavaScript, what will happen to the cookies.txt data if the file exceeds the
maximum size?
Answers:
• The script
automatically generates a run-time error.
• The script automatically
generates a load-time error.
• All processes
using document.cookie are ignored.
• The file is truncated to
the maximum length.
70. Which of the following are not
global methods and properties in E4X?
Answers:
• ignoreComments
• ignoreWhiteSpace
• setName()
• setNamespace()
• ignoreComments
and ignoreWhiteSpace
• setName() and
setNamespace()
71. What is the purpose of while(1) in
the following JSON response?
while(1);[['u',[['smsSentFlag','false'],['hideInvitations','false'],['remindOnRespondedEventsOnly','true'],['hideInvitations_remindOnRespondedEventsOnly','false_true'],['Calendar
ID stripped for privacy','false'],['smsVerifiedFlag','true']]]]
Answers:
• It's invalid
JSON code.
• It makes it difficult for
a third-party to insert the JSON response into an HTML document with a
<script> tag.
• It iterates the
JSON response.
• It prevents the
JSON response from getting executed.
72. Consider the three variables:
someText = 'JavaScript1.2';
pattern = /(\w+)(\d)\.(\d)/i;
outCome = pattern.exec(someText);
What does outCome[0] contain?
Answers:
• true
• false
• JavaScript1.2
• null
• 0
73. Which of the following determines
whether cookies are enabled in a browser or not?
Answers:
•
(navigator.Cookie)? true : false
• (application.cookieEnabled)?
true : false
• (navigator.cookieEnabled)?
true : false
•
(application.cookie)? true : false
74. How can global variables be
declared in JavaScript?
Answers:
• All variables
are local in JavaScript.
• Declare the variable
between the 'script' tags, and outside a function to make the variable global
• Precede the
variable name with the constant global
• Declare the
variable in an external file
75. What will be output of the
following code?
function testGenerator() {
yield
"first";
document.write("step1");
yield
"second";
document.write("step2");
yield
"third";
document.write("step3");
}
var g = testGenerator();
document.write(g.next());
document.write(g.next());
Answers:
• firststep1second
• step1step2
• step1
• step1step2step3
76. Which of the following methods
will copy data to the Clipboard?
Answers:
•
execClipboard('Copy')
•
copyCommand('Clipboard')
• execCommand('Copy')
•
execClipboard('Copy')
77. Which of the following code
snippets trims whitespace from the beginning and end of the given string str?
Answers:
• str.replace(/^\s+|\s+$/g,
'');
•
str.replace(/^\s+/,'');
•
str.replace(/\s+$/,'');
•
str.replace(/\s+/g,' ');
78. What is the meaning of obfuscation
in JavaScript?
Answers:
• Obfuscation is
a keyword in JavaScript.
• Making code unreadable
using advanced algorithms.
• Decrypting
encrypted source code using advanced algorithms.
• None of these.
79. Which of the following JavaScript
Regular Expression modifiers finds one or more occurrences of a specific
character in a string?
Answers:
• ?
• *
• +
• #
80. Which of the following is not a
valid JavaScript operator?
Answers:
• |
• ===
• %=
• ^
81. Which of the following can be used
to invoke an iframe from a parent page?
Answers:
• window.frames
•
document.getElementById
•
document.getelementsbyname
•
document.getelementsbyclassname
82. What value would JavaScript assign
to an uninitialized variable?
Answers:
• NaN
• null
• undefined
• false
83. Which of the following are correct
values of variableC, and why?
<script>
variableA = [6,8];
variableB =[7,9];
variableC = variableA + variableB;
</script>
Answers:
• 6, 7, 8 and 9. The
+ operator is defined for arrays, and it concatenates strings, so it converts
the arrays to strings.
• 6, 15 and 9.
The + operator is defined for arrays, and it concatenates numbers, so it
converts the arrays to numbers.
• 6, 8, 7 and 9.
The + operator is defined for arrays, and it concatenates strings, so it
converts the arrays to strings.
• 6, 87 and 9. The +
operator is not defined for arrays, and it concatenates strings, so it converts
the arrays to strings.
84. Which of the following code
snippets will toggle a div element's background color?
<button
id="toggle">Toggle</button>
<div id="terd">Change
Background Color.</div>
Answers:
• <script>
var button = document.getElementById('toggle'); button.click = function() { terd.style.backgroundColor
= terd.style.backgroundColor == 'blue' ? 'red' : 'blue'; }; </script>
• <script>
var button = document.getElementById('toggle'); button.ready = function() {
terd.style.backgroundColor = terd.style.backgroundColor == 'blue' ? 'red' :
'blue'; }; </script>
• <script>
var button = document.getElementById('toggle'); button.focus = function() {
terd.style.backgroundColor = terd.style.backgroundColor == 'blue' ? 'red' :
'blue'; }; </script>
• <script> var button
= document.getElementById('toggle'); button.onclick = function() {
terd.style.backgroundColor = terd.style.backgroundColor == 'blue' ? 'red' :
'blue'; }; </script>
85. How can the user's previously
navigated page be determined using JavaScript?
Answers:
• It is not
possible in JavaScript. This can be done only through server-side scripting.
• Using the
document.referrer property
• Using the window object
• None of these
86. Which of the following is not a
valid method for looping an array?
Answers:
• var a= [1,2];
for (var i = 0; i < a.length; i++) { alert(a[i]); }
• var a= [1,2];
a.forEach( function(item) { alert(item); })
• var a= [1,2];
a.map( function(item) { alert(item); })
• var a= [1,2]; a.loop(
function(item) { alert(item); })
87. Which of the following correctly
sets a class for an element?
Answers:
•
document.getElementById(elementId).className = "Someclass";
•
document.getElementById(elementId).setAttribute("className",
"Someclass");
•
document.getElementById(elementId).class = "Someclass";
•
document.getElementById(elementId).style = "Someclass";
88. An HTML form contains 10
checkboxes all named "chkItems". Which JavaScript function can be
used for checking all the checkboxes together?
Answers:
• function
CheckAll() { for (z = 0; z < document.forms.chkItems.length; z++) {
document.forms.chkItems[z].checked=true } }
• function CheckAll() { for
(z = 0; z < document.forms[0].chkItems.length; z++) {
document.forms[0].chkItems[z].checked=true } }
• function
CheckAll() { for (z = 0; z < document.forms[0].chkItems.length; z++) {
document.forms[0].chkItems.list[z].checked=true } }
• function
CheckAll() { for (z = 0; z < document.forms[0].chkItems.length; z++) {
document.forms[0].chkItems.list[z].checked=false } }
