Explore topic-wise InterviewSolutions in .

Correct option is (b) stylesheet

The explanation: A web style sheet is a form of separation of presentation and content for web DESIGN in which the markup (i.e., HTML or XHTML) of a webpage CONTAINS the page’s semantic content and STRUCTURE, but does not define its VISUAL layout (style). The rel attribute must hold the value rel = ‘stylesheet’.

Correct option is (d) Parse identifiers

To elaborate: A rendering ENGINE is SOFTWARE that DRAWS text and images on the screen. All of the mentioned belongs to the Render Engine workflow. The Render engine workflow contains:

Parse Content

Build DOM nodes in render tree

Layout positioning of DOM ELEMENTS

Paint DOM elements.

Right OPTION is (c) Network Layer

Explanation: The network layer is the third level of the Open Systems INTERCONNECTION Model (OSI Model) and the layer that provides DATA routing paths for network communication. The network layer RETRIEVES the content from the network.

Right ANSWER is (c) Ready for navigation

To explain I would say: The PerformanceTiming.navigationStart read-only PROPERTY returns an UNSIGNED long long representing the moment, in milliseconds 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.

The correct answer is (C) text/css

To EXPLAIN: Since the type of FILE is CSS, the type attribute should hold the value text/css. For javascript file type attribute WOULD hold the VALE text/js.

Correct option is (c) Time of navigation and page load event

For explanation I would say: 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. The legacy Performance.timing read-only property returns a PerformanceTiming object CONTAINING latency-related performance INFORMATION.

Correct OPTION is (d) Document begins to LOAD

Easiest explanation: domLoading is the TIME immediately before the USER agent SETS the current document readiness to ‘loading’. The domLoading attribute is used when the document begins to load.

The CORRECT CHOICE is (d) FileUpLoad

Best EXPLANATION: The Input FileUpload object represents an HTML ELEMENT with type=”file”. The FileUpLoad is a client-side JAVASCRIPT object.

Correct option is (C) 4

Explanation: The type property SETS or returns the value of the type attribute of an

The CORRECT ANSWER is (c) Both Undefined values and Functions WITHIN an object

To elaborate: JSON.stringify does not serialize undefined values or functions within an object. JSON.stringify() converts a JavaScript object into a string.

Correct option is (a) performance.MEMORY

To ELABORATE: The property performance.memory gives access to the JavaScript memory USAGE DATA. It returns an object of TYPE ObjectObject.

Correct option is (a) 21

For explanation I WOULD SAY: PERFORMANCE.timing read-only property returns a PerformanceTiming object CONTAINING latency-related performance information. There are a total of 23 properties associated with the interface PerformanceTiming.

The CORRECT ANSWER is (b) How the user navigated

To explain I WOULD SAY: The NAVIGATION tells how the user navigated to the page.

Correct answer is (b) Create inline JAVASCRIPT

For EXPLANATION I WOULD say: 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, for example:

Right option is (B) JavaScript Interpreter

To explain I would say: A JavaScript engine is a computer program that executes JavaScript (JS) CODE. The first JS engines were mere interpreters, but all relevant MODERN engines utilize just-in-time compilation for IMPROVED performance. The JavaScript Interpreter runs the JavaScript code.

The correct answer is (C) totalJsHeapSize

To explain I would SAY: usedJsHeapSize stores an object CREATED with MemoryInfo constructor, CONTAINING jsHeapSizeLimit, totalJSHeapSize and usedJSHeapSize properties with numerical VALUES.

Correct answer is (a) Amount of memory used

To EXPLAIN I WOULD SAY: usedJsHeapSize returns an object of type ObjectObject. An object created with MemoryInfo CONSTRUCTOR, containing jsHeapSizeLimit, totalJSHeapSize and usedJSHeapSize properties with numerical values. The usedJsHeapSize property is the amount of memory that all of the CURRENT objects in the heap are using.

Right OPTION is (a) Navigation via BROWSER HISTORY

For explanation I WOULD say: TYPE_BACK_FORWARD performs navigation through a history traversal operation. 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.

The correct answer is (d) TYPE_RESERVED

The explanation: TYPE_BACK_FORWARD performs NAVIGATION through a history traversal operation. TYPE_RESERVED Has the VALUE of 255 and is a catch-all for any navigation TYPE not defined above.

Right choice is (b) s.on(“end”,f);

The explanation is: In COMPUTING, end-of-file (commonly ABBREVIATED EOF) is a condition in a computer operating system where no more DATA can be read from a data source. The above code snippet GETS “end” EVENT fired on EOF when no more data will arrive.

The correct option is (c) Gets MEMORY USAGE

To elaborate: The JavaScript Memory column represents the JS heap. This column contains two values. The value you’re interested in is the LIVE number (the number in parentheses). 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.

Correct answer is (a) PROFILING

The best EXPLANATION: Garbage collected languages help developers MANAGE MEMORY by periodically checking which previously allocated pieces of memory can still be “reached” from other parts of the application. Profiling ALLOWS us to monitor our memory usage.

Right choice is (d) PROTOTYPE object

Easiest explanation: A prototype is an object that is associated with EVERY functions and object by default in JavaScript, where function’s prototype property is accessible and modifiable and object’s prototype property (aka attribute) is not visible. The properties of the prototype object are inherited by all instances of the class, and properties WHOSE values are functions BEHAVE LIKE instance methods of the class.

Right CHOICE is (c) Returns the VALUE of cursor-selected text

The best I can explain: The Window.GETSELECTION() method returns a Selection object representing the range of text selected by the USER or the current POSITION of the caret. The getSelection() method returns the value of the cursor-selected text.

Correct answer is (d) True

The EXPLANATION: The ASYNC attribute is a boolean attribute. When present, it specifies that the script will be executed asynchronously as soon as it is AVAILABLE. The async attribute optionally ACCEPTS a boolean value and by default HOLDS the value true.

The correct answer is (c) INVOKE code during downloading

Easy explanation: 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:

The correct CHOICE is (d) Build DOM nodes in RENDER tree

Explanation: After EXECUTING the script, the DOM nodes will be BUILT in the render tree. The Render engine workflow contains:

PARSE Content

Build DOM nodes in render tree

Layout positioning of DOM elements

Paint DOM elements.

The correct ANSWER is (b) performance.memory. jsHeapSizeLimit

Explanation: Memory CONTAINS an object created with MemoryInfo constructor, CONTAINING jsHeapSizeLimit, totalJSHeapSize and usedJSHeapSize properties with numerical values. The command performance.memory. jsHeapSizeLimit is used to access the HEAP SIZE limit.

The correct option is (b) 2

Easy explanation: There are a total of 2 properties ASSOCIATED with the Response event namely:

PerformanceTiming.responseEnd

PerformanceTiming.responseStart.

PerformanceTiming.responseStart read-only PROPERTY returns an unsigned LONG long representing the moment in time (in milliseconds since the UNIX epoch) when the browser received the first byte of the response from the server, cache, or local resource.

Right answer is (a) BROWSER

The EXPLANATION is: DNS is a query/response protocol. The client queries information (for example the IP address corresponding to www.google.com) in a single UDP REQUEST. The DNS reply GOES to the Browser in a single HTTP redirect.

The correct answer is (c) PerformanceTiming.navigationStart & PerformanceTiming.fetchStart

For explanation I WOULD say: 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. Both PerformanceTiming.navigationStart and also the PerformanceTiming.fetchStart are a read-only PROPERTIES.

The CORRECT answer is (c) Switches to Javascript Interpreter

To explain I would say: A rendering engine is a software that draws text and images on the SCREEN. The rendering engine HANDLES PAINTING the content to the screen. When it encounters JavaScript, it hands it off to the JavaScript interpreter.

The correct answer is (c) Appends a node as the LAST CHILD

The best explanation: The appendChild() method appends a node as the last child of a node. You can also use this method to move an element from ONE element to another.

Right choice is (a) After window.onload EVENT

The EXPLANATION: 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. 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.

Correct option is (a) If the reference string comes before or after another string

Explanation: The localeCompare() method compares two strings in the current LOCALE. The locale is based on the language settings of the BROWSER. 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.

The correct choice is (c) Load JAVASCRIPT files PROGRAMMATICALLY

Easy explanation: The script loading loads remote JavaScript files programmatically and allow us to trick the rendering engine. The async attribute is a BOOLEAN attribute. When PRESENT, it SPECIFIES that the script will be executed asynchronously as soon as it is available.

Right answer is (C) 3

Best explanation: Advanced JavaScript APPLICATION features such as caches and UNDO buffers need to know the memory consumption of objects in ORDER to function effectively. There are a total of 3 memory objects namely:

jsHeapSizeLimit

totalJsHeapSize

usedJsHeapSize.

Correct OPTION is (b) performance.navigation.redirectCount

The EXPLANATION is: The redirectCount property can be accessed as performance.navigation.redirectCount. The PerformanceNavigation.redirectCount read-only property returns an unsigned SHORT representing the number of REDIRECTs DONE before reaching the page.

The correct choice is (b) Browser ready to fetch DOCUMENT

To explain I WOULD say: The PerformanceTiming.fetchStart read-only property RETURNS an unsigned long long representing the moment, in MILLISECONDS since the UNIX epoch, the browser is ready to fetch the document using an HTTP REQUEST. If there is no previous document, this value will be the same as PerformanceTiming.fetchStart.