Invocation And Performance Navigation
Name: _____________________
Date: _____________________
Instructions: Answer all questions. Write your answers clearly in the space provided.
Question 1:
What is the inital step to set up a CSS Lazy Loading?
A.
Fetching data
B.
Loading the script
C.
Loading the page
D.
Adding the event listener
Answer: _________
Question 2:
What is the purpose of holding whatever tag you create in the attribute type?
A.
To have more information
B.
To identify the scripting language
C.
All of the mentioned
D.
None of the mentioned
Answer: _________
Question 3:
What does the appendChild() method perform?
A.
Appends a node in the middle of the index taken as the parameter
B.
Appends a node as the first child
C.
Appends a node as the last child
D.
None of the mentioned
Answer: _________
Question 4:
What should be the value of the type attribute of a variable if the type of file is CSS?
A.
text/js/css
B.
text/js
C.
text/css
D.
text
Answer: _________
Question 5:
How to lazy load images?
A.
Remove the rel attribute
B.
Remove the src attribute
C.
Make rel = src
D.
Make src = rel
Answer: _________
Question 6:
What does the rel attribute of a variable have when the type of file is CSS?
A.
css
B.
stylesheet
C.
text/css
D.
all of the mentioned
Answer: _________
Question 7:
What is the parameter of the method getElementsbyTagName() if we need to get an image?
A.
image
B.
src
C.
img
D.
imageurl
Answer: _________
Question 8:
How do we stop blocking of loading and executing the perfLogger, a logging type data?
A.
Inlining the perfLogger
B.
Removing the perfLogger
C.
Placing the perfLogger before the “script” tag
D.
None of the mentione
Answer: _________
Question 9:
When does the browser stop rendering the HTML?
A.
Inline JavaScript block
B.
External JavaScript file
C.
Both Inline JavaScript block & External JavaScript file
D.
None of the mentioned
Answer: _________
Question 10:
Which of the following handles painting the content on to the screen?
A.
Rendering engine
B.
JavaScript Interpreter
C.
UI Layer
D.
Network Layer
Answer: _________
Question 11:
What does the rendering engine do when it encounters JavaScript?
A.
Skips the code
B.
Continues painting
C.
Switches to Javascript Interpreter
D.
None of the mentioned
Answer: _________
Question 12:
Which of the following runs the JavaScript code?
A.
Just In Time compiler
B.
JavaScript Interpreter
C.
Both Just In Time compiler and JavaScript Interpreter
D.
None of the mentioned
Answer: _________
Question 13:
Which of the following layer retrieves the content from the network?
A.
Transport Layer
B.
Application Layer
C.
Network Layer
D.
Physical Layer
Answer: _________
Question 14:
Which of the following gets converted to DOM elements by the rendering engine?
A.
Tokens
B.
Strings
C.
Address
D.
All of the mentioned
Answer: _________
Question 15:
Which of the below does not belong to the Render Engine work flow?
A.
Paint DOM elements
B.
Parse Content
C.
uild DOM nodes in render tree
D.
None of the mentioned
Answer: _________
Question 16:
Which is the next step after retrieving the content in chunks?
A.
Paint DOM elements
B.
Parse Content
C.
Build DOM nodes in render tree
D.
None of the mentioned
Answer: _________
Question 17:
What will happen after executing the script?
A.
Execute script
B.
Layout positioning of DOM elements
C.
Paint DOM elements
D.
Build DOM nodes in render tree
Answer: _________
Question 18:
What would happen if there were no script tags?
A.
Build DOM nodes in render tree
B.
Layout positioning of DOM elements
C.
Paint DOM elements
D.
Execute script
Answer: _________
Question 19:
How many properties are available in a memory object?
A.
1
B.
2
C.
3
D.
4
Answer: _________
Question 20:
What is a heap in JavaScript?
A.
Collection of Java objects
B.
Collection of JavaScript objects
C.
Collection of memory usage values
D.
Collection of data stored in memory
Answer: _________
Question 21:
What is the function of the memory object?
A.
Gets unused memory details
B.
Shows optimization
C.
Gets memory usage
D.
None of the mentioned
Answer: _________
Question 22:
What is the command to access the Heap size limit?
A.
performance.memory. SizeLimit
B.
performance.memory. jsHeapSizeLimit
C.
jsHeapSizeLimit
D.
performance.jsHeapSizeLimit
Answer: _________
Question 23:
What is the purpose of garbage collection?
A.
Removes object with many reference
B.
Removes object with reference
C.
Removes object with invalid reference
D.
Removes object with no reference
Answer: _________
Question 24:
What does the usedJsHeapSize property indicate?
A.
Amount of memory used
B.
Amount of memory unused
C.
Amount of memory used & unused
D.
None of the mentioned
Answer: _________
Question 25:
Which of the following property indicate the total size of heap?
A.
heapSize
B.
totalHeapSize
C.
totalJsHeapSize
D.
totalHeap
Answer: _________
Question 26:
What can be done to monitor the memory usage?
A.
Profiling
B.
Sequencing
C.
Serializing
D.
None of the mentioned
Answer: _________
Question 27:
Which of the following gives the high level breakdown of memory usage?
A.
about:memory
B.
memory
C.
about-memory
D.
about::memory
Answer: _________
Question 28:
Which keyword must be used to get a more granular insight of the memory usage?
A.
verb
B.
verbose
C.
granule
D.
none of the mentioned
Answer: _________
Question 29:
What is the purpose of lazy loading?
A.
Immediate loading is necessary
B.
Loading under command
C.
Immediate loading is not necessary
D.
None of the mentioned
Answer: _________
Question 30:
Where is the external JavaScript placed in the case of lazy loading?
A.
After window.onload event
B.
Before window.onload event
C.
All of the mentioned
D.
None of the mentioned
Answer: _________
Question 31:
What are the parameters of the attachEvent function?
A.
Function
B.
Function, Event
C.
Event, Function
D.
Event
Answer: _________
Question 32:
What is the result when the showPerformanceMetrics() is called before loading the remote script?
A.
Throws an exception
B.
Throws an error
C.
It will load by itself
D.
None of the mentioned
Answer: _________
Question 33:
Which of the following is an attribute to the script object?
A.
onclick
B.
onload
C.
onshow
D.
all of the mentioned
Answer: _________
Question 34:
Which is the method used to add an event listener?
A.
addEventListener()
B.
addListener()
C.
addEvent(Listener)
D.
addListener(Event)
Answer: _________
Question 35:
What is the purpose of the domLoading attribute?
A.
Document exists
B.
Document can load
C.
Document has loaded
D.
Document begins to load
Answer: _________
Question 36:
How is the render time calculated?
A.
Date.Now()
B.
Date.Now() – performance.timing.domLoading
C.
performance.domLoading
D.
Date.Now() – performance.domLoading
Answer: _________
Question 37:
The object whose properties are inherited by all instances of the class, and properties whose values are functions behaving like instance methods of the class, is
A.
Instance object
B.
Constructor object
C.
Destructor object
D.
Prototype object
Answer: _________
Question 38:
You can refresh the webpage in JavaScript by using
A.
window.reload
B.
location.reload
C.
window.refresh
D.
page.refresh
Answer: _________
Question 39:
How many properties does a prototype object have?
A.
6
B.
7
C.
8
D.
9
Answer: _________
Question 40:
Which of the following does not serialize the undefined values or objects within an object?
A.
JSON.string
B.
JSON
C.
JSON.stringify
D.
None of the mentioned
Answer: _________
Question 41:
How many properties are there in the interface PerformanceTiming?
A.
21
B.
22
C.
23
D.
24
Answer: _________
Question 42:
How many properties are there in window.performance object?
A.
1
B.
4
C.
2
D.
3
Answer: _________
Question 43:
What is the purpose of the navigation property in the window.performance object?
A.
To which page the user navigated
B.
How the user navigated
C.
All of the mentioned
D.
None of the mentioned
Answer: _________
Question 44:
What is the purpose of the property PerformanceTiming.navigationStart?
A.
Ready to end the navigation
B.
Ready to jump the navigation
C.
Ready for navigation
D.
None of the mentioned
Answer: _________
Question 45:
Which of the following does JSON.stringify not serialize?
A.
Undefined values
B.
Functions within an object
C.
Both Undefined values and Functions within an object
D.
None of the mentioned
Answer: _________
Question 46:
What is the purpose of the property PerformanceTiming.fetchStart?
A.
Browser ready to fetch input
B.
Browser ready to fetch document
C.
Browser ready to fetch summary
D.
All of the mentioned
Answer: _________
Question 47:
Which of the following property is associated with the Request event?
A.
requestStart
B.
requestEnd
C.
both requestStart and requestEnd
D.
none of the mentioned
Answer: _________
Question 48:
Which of the following API can be used to get the timing without affecting the page loading process?
A.
Navigation API
B.
Timing API
C.
Navigation Timing API
D.
None of the mentioned
Answer: _________
Question 49:
How many read-only attributes are present in the navigator object?
A.
1
B.
2
C.
3
D.
4
Answer: _________
Question 50:
Why are HTTP redirects significant?
A.
TCP connection available
B.
Complete roundtrip absent
C.
Complete roundtrip present
D.
None of the mentioned
Answer: _________
Question 51:
Where does the DNS reply go to in a single HTTP redirect?
A.
Browser
B.
Client
C.
Server
D.
DNS Server
Answer: _________
Question 52:
How can one access the redirectCount property?
A.
navigation.redirectCount
B.
performance.navigation.redirectCount
C.
performance.redirectCount
D.
redirectCount
Answer: _________
Question 53:
How many constant values can the property type be represented?
A.
2
B.
3
C.
4
D.
5
Answer: _________
Question 54:
Which of the following constants has the value 255?
A.
TYPE_NAVIGATE
B.
TYPE_RELOAD
C.
TYPE_BACK_FORWARD
D.
TYPE_RESERVED
Answer: _________
Question 55:
What is the purpose of the constant TYPE_RELOAD?
A.
Reload performed
B.
Reload not performed
C.
Reload must be performed
D.
None of the mentioned
Answer: _________
Question 56:
What does the constant TYPE_BACK_FORWRD indicate?
A.
Navigation via browser history
B.
Navigation via user request
C.
Navigation via URL
D.
None of the mentioned
Answer: _________
Question 57:
Which of the following constants hold the value 2?
A.
TYPE_NAVIGATE
B.
TYPE_RELOAD
C.
TYPE_BACK_FORWARD
D.
TYPE_RESERVED
Answer: _________
Question 58:
Where does the DNS Lookup direct to ?
A.
Browser
B.
Client
C.
Server
D.
DNS Server
Answer: _________
Question 59:
What is the purpose of the method createDocumentFragment()?
A.
Creates a fragment object
B.
Creates a document fragment
C.
Creates imaginary node object
D.
None of the mentioned
Answer: _________
Question 60:
What is the default value of the asyc attribute?
A.
0
B.
1
C.
False
D.
True
Answer: _________
Question 61:
What is the method to create a data frame ?
A.
frame(data)
B.
frameData()
C.
data.frame()
D.
none of the mentioned
Answer: _________
Question 62:
What is the purpose of creating a data frame?
A.
Hold the page render time
B.
Hold the load time
C.
Hold the page render time & load time
D.
None of the mentioned
Answer: _________
Question 63:
Which of the following navigator object properties is the same in both Netscape and IE?
A.
navigator.appCodeName
B.
navigator.appName
C.
navigator.appVersion
D.
none of the mentioned
Answer: _________
Question 64:
Which best explains getSelection()?
A.
Returns the VALUE of a selected OPTION
B.
Returns document.URL of the window in focus
C.
Returns the value of cursor-selected text
D.
Returns the VALUE of a checked radio input
Answer: _________
Question 65:
Which of the following are client-side JavaScript object?
A.
Database
B.
Cursor
C.
Client
D.
FileUpLoad
Answer: _________
Question 66:
What is the purpose of the method localeCompare()?
A.
If the reference string comes before or after another string
B.
If the reference string is validated
C.
If the string is a reference string
D.
None of the mentioned
Answer: _________
Question 67:
Which of the following property gives access to the JavaScript memory usage data?
A.
performance.memory
B.
memory(performance)
C.
performance(memory)
D.
none of the mentioned
Answer: _________
Question 68:
What is the purpose of the timing property in the window.performance object?
A.
Time of navigation event
B.
Time of page load event
C.
Time of navigation and page load event
D.
None of the mentioned
Answer: _________
Question 69:
Which of the following property is associated with the Response event?
A.
responseStart
B.
responseEnd
C.
both responseStart and responseEnd
D.
none of the mentioned
Answer: _________
Question 70:
Which of the following computation is correct to calculate the time taken for page load once the page is received from the server?
A.
responseEnd-loadEventEnd
B.
loadEventEnd-responseEnd
C.
loadEventEnd/responseEnd
D.
responseEnd/loadEventEnd
Answer: _________
Question 71:
Which of the following property is associated with the Processing event?
A.
domComplete
B.
domContentLoaded
C.
domInteractive
D.
none of the mentioned
Answer: _________
Question 72:
What does it indicate when the type attribute of the navigation object is set to 2?
A.
Navigation by moving back through history
B.
Navigation by moving forward through history
C.
Navigation by moving back & forward through history
D.
None of the mentioned
Answer: _________
Question 73:
What does the method Performance.now() return?
A.
DOMTimeStamp
B.
DOMHighResTimeStamp
C.
DOMStamp
D.
TimeStamp
Answer: _________
Question 74:
Which of the following is a read-only property?
A.
PerformanceTiming.navigationStart
B.
PerformanceTiming.fetchStart
C.
PerformanceTiming.navigationStart & PerformanceTiming.fetchStart
D.
None of the mentioned
Answer: _________
Question 75:
Which of the following is an interface?
A.
Time
B.
Timing
C.
Performance
D.
PerformanceTiming
Answer: _________
Question 76:
How many properties are associated with the Response event?
A.
1
B.
2
C.
3
D.
4
Answer: _________
Question 77:
What is the purpose of script loading?
A.
Load Scripts programmatically
B.
Load JavaScript files manually
C.
Load JavaScript files programmatically
D.
All of the mentioned
Answer: _________
Question 78:
What will happen if the browser encounters a script tag without an src attribute?
A.
Throws an error
B.
Throws an exception
C.
Sends it to the compiler
D.
Sends it to the interpreter
Answer: _________
Question 79:
What is the solution to the absence of a script tag without an src attribute?
A.
Resend the scripts
B.
Create inline JavaScript
C.
All of the mentioned
D.
None of the mentioned
Answer: _________
Question 80:
How to get a particular value using the tagged name?
A.
getElementbyID()
B.
getElementsbyName()
C.
getElementsbyTagName()
D.
getTagName()
Answer: _________
Question 81:
What should be the type of the script_url?
A.
Object
B.
String
C.
Array
D.
Any of the mentioned
Answer: _________
Question 82:
What is the purpose of using the async attribute in the script tag?
A.
Load the script asynchronously
B.
Load the script synchronously
C.
Load the page asynchronously
D.
Load the page synchronously
Answer: _________
Question 83:
Why do we need to use an onload event in the script tag after using the async attribute?
A.
Invoke code during page loading
B.
Invoke code during script loading
C.
Invoke code during downloading
D.
None of the mentioned
Answer: _________
Question 84:
What is the purpose of the startTimeLogging() method?
A.
Start the timer
B.
Capture time logging
C.
Capture timing data for referencing
D.
All of the mentioned
Answer: _________
Question 85:
What is the type of datatype the async attribute optionally accepts?
A.
Integer
B.
String
C.
Boolean
D.
Decimal
Answer: _________
Question 86:
What is the method used to create an element in the HTML DOM?
A.
createDOMelement()
B.
createElement()
C.
createDOMElement()
D.
none of the mentioned
Answer: _________
Question 87:
When the “end” event fires on EOF when no more data will arrive, which function is called?
A.
s.on("data",f)
B.
s.on("end",f)
C.
s.on("error",f)
D.
s.on("default",f)
Answer: _________
Question 88:
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: _________
Answer Key
1:
A
Solution: The CSS Lazy Loading is begun with fetching the JavaScript and the CSS files.
2:
B
Solution: A variable is created to hold whatever taag you create, and then branch the logic based on the value of type, which identifies it’s for JavaScript or for CSS.
3:
C
Solution: The appendChild() method appends a node as the last child of a node.
4:
C
Solution: Since the type of file is CSS, the type attribute should hold the value text/css.
5:
B
Solution: The way we would lazy load images would be to alter the HTML of the page to remove the contents of the src attribute of each image. We could just move the contents of the src attribute to an attribute in the image tag of our own design, maybe the rel attribute.
6:
B
Solution: The rel attribute must hold the value rel = ‘stylesheet’.
7:
C
Solution: The method must look like getElementsbyTageName(“img”) if we need to get an image.
8:
A
Solution: By inlining the perfLogger, we no longer block the loading and executing of it.
9:
C
Solution: When the browser parses the HTML markup, it stops rendering the HTML when it encounters an inline JavaScript block or external JavaScript file. At this point, the user experiences rendering delays. Moving the JavaScript to the end of the HTML markup would completely eliminate these pauses in rendering.
10:
A
Solution: The rendering engine handles painting the content to the screen. When it encounters JavaScript, it hands it off to the JavaScript interpreter.
11:
C
Solution: The rendering engine handles painting the content to the screen. When it encounters JavaScript, it hands it off to the JavaScript interpreter.
12:
B
Solution: The JavaScript Interpreter runs the JavaScript code.
13:
C
Solution: he network layer retrieves the content from the network.
14:
A
Solution: The string returned by the network layer gets tokenized into meaningful chunks. The rendering engine then takes the tokens and converts them to DOM elements.
15:
D
Solution: All of the mentioned belongs to the Render Engine work flow. The Render engine work flow contains : 1. Parse Content 2. Build DOM nodes in render tree 3. Layout positioning of DOM elements 4. Paint DOM elements.
16:
B
Solution: After retrieving the content in chunks, the contents will be parsed.
17:
D
Solution: After executing the script, the DOM nodes will be built in the render tree.
18:
A
Solution: If there were no script tags, the DOM nodes will be built in the render tree.
19:
C
Solution: There are a total of 3 memory objects namely : 1. jsHeapSizeLimit 2. totalJsHeapSize 3. usedJsHeapSize
20:
B
Solution: The heap is the collection of JavaScript objects that the interpreter keeps in resident memory.
21:
C
Solution: The memory object is a feature of Chrome that allows us to see the memory usage that Chrome is taking up while running our page.
22:
B
Solution: The command performance.memory. jsHeapSizeLimit is used to access the Heap size limit.
23:
D
Solution: When the interpreter sees an object in the heap with no object references, it removes that object from the heap. This is called garbage collection.
24:
A
Solution: The usedJsHeapSize property is the amount of memory that all of the current objects in the heap are using.
25:
C
Solution: The totalJsHeapSize is size of the heap including free space not used by objects.
26:
A
Solution: Profiling allows us to monitor our memory usage.
27:
A
Solution: Typing about:memory into the location bar brings up a page that gives a high-level breakdown of memory usage.
28:
B
Solution: To get a more granular insight of the memory usage, we must type about:memory?verbose.
29:
C
Solution: Lazy loading is a kind of loading in which we don’t need our JavaScript code to be available as soon as the page loads.
30:
A
Solution: When we don’t need our JavaScript code to be available as soon as the page loads, we can script-load our external JavaScript after the window.onload event.
31:
C
Solution: The attachEvent function accepts two parameters: the event to attach to, and the function to invoke when the event occurs.
32:
B
Solution: If you try to make the call to perfLogger.showPerformanceMetrics() and the script hasn’t just loaded but also executed, then you will get an error.
33:
B
Solution: Only onload is an attribute to the script object.
34:
A
Solution: The addEventListener() method is used to add an event listener to the script.
35:
D
Solution: The domLoading attribute is used when the document begins to load.
36:
B
Solution: The render time is calculated as Date.Now() – performance.timing.domLoading.
37:
D
Solution: The properties of the prototype object are inhertied by all instances of the class, and properties whose values are functions behave like instance methods of the class.
38:
B
Solution: One can refresh the webpage in JavaScript by using location.reload.
39:
B
Solution: There are a total of 7 properties in the prototype object namely : 1. perceivedTime 2. redirectTime 3. cacheTime 4. dnsLookupTime 5. tcpConnectionTime 6. roundTripTime 7. pageRenderTime
40:
C
Solution: JSON.stringify does not serialize undefined values or functions within an object.
41:
A
Solution: There are a total of 23 properties associated with the interface PerformanceTiming.
42:
C
Solution: There are totally 2 properties associated with the window.performance and they are: 1. navigation 2. type
43:
B
Solution: The navigation tells how the user navigated to the page.
44:
C
Solution: The PerformanceTiming.navigationStart read-only property returns an unsigned long long representing the moment, in miliseconds since the UNIX epoch, right after the prompt for unload terminates on the previous document in the same browsing context. If there is no previous document, this value will be the same as : PerformanceTiming.fetchStart.
45:
C
Solution: JSON.stringify does not serialize undefined values or functions within an object.
46:
B
Solution: The PerformanceTiming.fetchStart read-only property returns an unsigned long long representing the moment, in miliseconds since the UNIX epoch, the browser is ready to fetch the document using an HTTP request.
47:
A
Solution: The Request event has only one property : requestStart.
48:
C
Solution: The timing code is in the page, so it affects how the page loads and the time that takes.. The Navigation Timing API can be used to get the timing without affecting the page loading process.
49:
B
Solution: There are a total of 2 read-only attributes present in the navigator object namely : 1. redirectCount 2. type
50:
B
Solution: HTTP redirects are significant because they cause a complete roundtrip for each redirect. The original request is returned from the web server as either a 301 or a 302 with the path to the new location. The browser must then initialize a new TCP connection and send a new request for the new location.
51:
A
Solution: The DNS reply goes to the Browser in a single HTTP redirect.
52:
B
Solution: The redirectCount property can be accessed as : performance.navigation.redirectCount.
53:
C
Solution: Totally 4 constant values can be represented by the property type.
54:
D
Solution: TYPE_RESERVED: Has the value of 255 and is a catch-all for any navigation type not defined above.
55:
A
Solution: TYPE_RELOAD: Has the value of 1, indicating that the current page was arrived at via a reload operation.
56:
A
Solution: TYPE_BACK_FORWARD: Has the value of 2, indicating that the page was navigated to via the browser history, either using the back or forward buttons or programmatically through the browser’s history object.
57:
C
Solution: TYPE_BACK_FORWARD: Has the value of 2, indicating that the page was navigated to via the browser history, either using the back or forward buttons or programmatically through the browser’s history object.
58:
D
Solution: The DNS Lookup directs to the DNS Server.
59:
C
Solution: The createDocumentFragment() method creates a imaginary Node object, with all the properties and methods of the Node object.
60:
D
Solution: The async attribute optionally accepts a boolean value and by default holds the value true.
61:
C
Solution: The method to create a data frame is data.frame().
62:
C
Solution: You can create a data frame to hold the mean page render times for each test URL, and a data frame to hold the mean load time for each test URL.
63:
A
Solution: The property navigator.appCodeName is the same in both Netscape and IE.
64:
C
Solution: The getSelection() method returns the value of the cursor-selected text.
65:
C
Solution: Client-side JavaScript objects refer to objects that are available within the browser environment and interact directly with the user or the browser's document model. Option A: Database - This is not a client-side JavaScript object. Databases are typically managed server-side or through external services. Option B: Cursor - This is not a client-side JavaScript object. While cursors are used in database operations, they are not part of the JavaScript object model in the browser. Option C: Client - This is the correct answer. Client-side JavaScript objects include the browser's window, document, navigator, and other objects that interact directly with the user's interface. Option D: FileUpload - This is not a standard client-side JavaScript object. File uploads are handled via HTML input elements and server-side processing, though JavaScript can interact with these elements. Conclusion: In JavaScript, client-side objects are those that interact directly with the browser environment and user interface. Among the given options, only the Client is a client-side JavaScript object, making Option C the correct answer. Other options like Database , Cursor , and FileUpload are not considered standard client-side JavaScript objects.
66:
A
Solution: The method localeCompare() returns a number indicating whether a reference string comes before or after or is the same as the given string in sort order.
67:
A
Solution: The property performance.memory gives access to the JavaScript memory usage data.
68:
C
Solution: Each performance.timing attribute shows the time of a navigation event (such as when the page was requested) or page load event (such as when the DOM began loading), measured in milliseconds.
69:
C
Solution: The properties associated with the Response event are : 1. responseStart 2. responseEnd.
70:
B
Solution: The time taken for page load once the page is received from the server: loadEventEnd-responseEnd .
71:
D
Solution: The following properties are associated with the Processing event : 1. domComplete 2. domContentLoaded 3. domInteractive 4. domLoading 5. unLoadEnd
72:
C
Solution: When the type attribute of the navigation object is set to 2, it means that the navigation is done by moving back or forward through history.
73:
B
Solution: The Performance.now() method returns a DOMHighResTimeStamp, measured in milliseconds, accurate to one thousandth of a millisecond equal to the number of milliseconds since the PerformanceTiming.navigationStart property and the call to the method.
74:
C
Solution: Both PerformanceTiming.navigationStart and also the PerformanceTiming.fetchStart are a read-only properties.
75:
D
Solution: PerformanceTiming is an interface in JavaScript.
76:
B
Solution: There are a total of 2 properties associated with the Response event namely : 1. PerformanceTiming.responseEnd 2. PerformanceTiming.responseStart
77:
C
Solution: The script loading loads remote JavaScript files programmatically and allows us to trick the rendering engine.
78:
D
Solution: If the browser encounters a script tag without a src attribute, the rendering engine simply passes the code to the JavaScript Interpreter for execution.
79:
B
Solution: The solution to the absence of a script tag without an src attribute is to create inline JavaScript to append script tags to the document dynamically
80:
C
Solution: The method getElementsbyTagName() can be used to get a particular value using the tagged name associated with the document.
81:
D
Solution: The type of the script_url can be anything that will be compared with the typeof keyword’s result.
82:
A
Solution: The async option is a native attribute that will tell the browser to load the script asynchronously.
83:
C
Solution: When using async you don’t know when the file will be downloaded, so you can attach an onload event handler to the script tag. This will allow you to invoke or instantiate any code that will need to be run when the file is downloaded:
84:
D
Solution: The startTimeLogging() method captures the timing data for ad hoc, etc for referencing an uncached document.location.
85:
C
Solution: The async attribute optionally accepts the boolean datatype of default value as true.
86:
B
Solution: The createElement() can be used to create an element in the HTML DOM.
87:
B
Solution: The above code snippet gets “end” event fired on EOF when no more data will arrive.
88:
B
Solution: The sets object is the namespace for the module, and we define each of the set classes as a property of this object.