1. 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.
2. 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.
3. 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);
4. 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.
5. 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 };
6. 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)
7. 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>
8. Which object can be used to ascertain the protocol of the current URL?
Answers:
• document
• window
• history
• browser
• form
• location
9. 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.
10. 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.
11. Which of the following is not a valid HTML event?
Answers:
• ondblclick
• onmousemove
• onclick
• onblink
12. 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,
13. 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"
14. 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
15. 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
16. 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
17. 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"
18. 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()"
19. 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>
20. 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()
21. 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>
22. 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";
23. Which of the following results is returned by the JavaScript operator "typeof" for the keyword "null"?
Answers:
• function
• object
• string
• number
24. What will be the final value of the variable "apt"?
var apt=2;
apt=apt<<2;
Answers:
• 2
• 4
• 6
• 8
• 16
25. How can a JavaScript object be printed?
Answers:
• console.log(obj)
• console.print(obj)
• console.echo(obj);
• None of these
26. 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
27. 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")
28. 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()"
29. 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"; }
30. 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()"
31. Which of the following modifiers must be set if the JavaScript lastIndex object property was used during pattern matching?
Answers:
• i
• m
• g
• s
32. 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"
33. 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) {}
34. 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.
35. 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"
36. 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;
37. 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')"
38. 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
39. 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
40. Are the two statements below interchangeable?
object.property
object[''property'']
Answers:
• Yes
• No
41. Which of the following is not a valid method in generator-iterator objects in JavaScript?
Answers:
• send()
• throw()
• next()
• stop()
42. 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);
43. 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()"
44. 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
45. Which of the following Regular Expression pattern flags is not valid?
Answers:
• gi
• p
• i
• g
46. 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
47. 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");
48. 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 ()")
49. Which of the following can be used to escape the ' character?
Answers:
• *
• \
• -
• @
• #
• %
• |
• ~
50. 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
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