JS Quiz Exercise Lab

JavaScript
JavaScript

Front End Developers-Lab

(JS) JavaScript
Interview Questions and Anwsers

Practice Before Interview or Quiz

(JS) JavaScript is the programming language that runs in the browser, which is used to build advanced interactive Web sites and applications for secure browser execution.

JS Quiz Exercise Lab

What is Javascript?

JavaScript is the scripting language of the Web.JavaScript is used in millions of Web pages to add functionality, validate forms, detect browsers, and much more.

What Javascript can do?

What Javascript can do? As: JavaScript gives HTML designers a programming tool JavaScript can put dynamic text into an HTML page JavaScript can react to events JavaScript can read and write HTML elements.
- JavaScript can be used to validate data
- JavaScript can be used to detect the visitor's browser
- JavaScript can be used to create cookies

What is a Javascript statement?

A JavaScript statement is a command to a browser. The purpose of the command is to tell the browser what to do.

What is the difference between XML and HTML?

XML is not a replacement for HTML. XML and HTML were designed with different goals:
1- XML was designed to transport and store data, with focus on what data is.
2- HTML was designed to display data, with focus on how data looks.
The difference is
HTML is about displaying information, while XML is about carrying information.

What is a javascript object?

A collection of data containing both properties and methods. Each element in a document is an object. Using the DOM you can get at each of these elements/objects and do some cool sh*t.

Describe what event bubbling is?

Event bubbling causes all events in the child nodes to be automatically passed to its parent nodes. The benefit of this method is speed because the code only needs to traverse the DOM tree once.

Describe what "this" is in JavaScript?

In JavaScript, 'this' normally refers to the object which 'owns' the method, but it depends on how a function is called.

What is the difference between == and === ?

The 3 equal signs mean "equality without type coercion". Using the triple equals, the values must be equal in type as well.

== is equal to
=== is exactly equal to (value and type)
0==false // true
0===false // false, because they are of a different type
1=="1" // true, auto type coercion
1==="1" // false, because they are of a different type
Resources for this answer:

http://longgoldenears.blogspot.com/2007/09/triple-equals-in-javascript.html

Where do you place your JavaScript on the page?

It may depend on what you are using it for. There is some debate on this but generally a good question to ask to get an understanding of the JS knowledge. Answers:

What is a closure?

Closures are expressions, usually functions, which can work with variables set within a certain context. Or, to try and make it easier, inner functions referring to local variables of its outer function create closures. Resources for this answer:

What is Global Namespacing?

Resources for this answer:

http://elegantcode.com/2011/01/26/basic-javascript-part-8-namespaces/

           

"1" + 2 + "3" + 4;

What does the above statement evaluate to?

10
1234
37

1234

4 + 3 + 2 + "1"

What does the above statement evaluate to?

10
4321
91

var foo = 1;
function bar() {
	foo = 10;
	return;
	function foo() {}
}
bar();
alert(foo);

What is alerted?

1
10
Function
undefined
Error

function bar() {
    return foo;
    foo = 10;
    function foo() {}
    var foo = 11;
}
alert(typeof bar());

What is alerted?

number
function
undefined
Error

Function

var x = 3;

var foo = {
    x: 2,
    baz: {
        x: 1,
        bar: function() {
            return this.x;
        }
    }
}

var go = foo.baz.bar;

alert(go());
alert(foo.baz.bar());

What is the order of values alerted?

1, 2
1, 3
2, 1
2, 3
3, 1
3, 2

3, 1

var x   = 4,
    obj = {
        x: 3,
        bar: function() {
            var x = 2;
            setTimeout(function() {
                var x = 1;
                alert(this.x);
            }, 1000);
        }
    };
obj.bar();

What value is alerted?

1
2
3
4
undefined

x = 1;
function bar() {
    this.x = 2;
    return x;
}
var foo = new bar();
alert(foo.x);

What value is alerted?

1
2
undefined

function foo(a) {
    alert(arguments.length);
}
foo(1, 2, 3);

What value is alerted?

1
2
3
undefined

var foo = function bar() {}; 
alert(typeof bar);

What value is alerted?

function
object
undefined

undefined

var arr = [];
arr[0]  = 'a';
arr[1]  = 'b';
arr.foo = 'c';
alert(arr.length);

What value is alerted?

1
2
3
undefined

function foo(a) {
    arguments[0] = 2;
    alert(a);
}
foo(1);

What value is alerted?

1
2
undefined

function foo(){}
delete foo.length;
alert(typeof foo.length);

What value is alerted?

number
undefined
object
Error

Number

var foo = function foo() {
    console.log(foo === foo);  
};
foo();

What is printed in the console?

true
false
ReferenceError

true

function aaa() {
    return
    {
        test: 1
    };
}
alert(typeof aaa());

What does the above alert?

function
number
object
undefined

undefined

Number("1") - 1 == 0;

What is the result?

true
false
TypeError

true

(true + false) > 2 + true;

What is the result?

true
false
TypeError
NaN

false

function bar() {
    return foo;
    foo = 10;
    function foo() {}
    var foo = '11';
}
alert(typeof bar());

What is alerted?

number
function
undefined
string
Error

function

"1" - - "1";

What is the result?

0
2
11
"11"

var x = 3;

var foo = {
    x: 2,
    baz: {
        x: 1,
        bar: function() {
            return this.x;
        }
    }
}

var go = foo.baz.bar;

alert(go());
alert(foo.baz.bar());

What is the order of values alerted?

1, 2
1, 3
2, 1
2, 3
3, 1
3, 2

3, 1

new String("This is a string") instanceof String;

What is the result?

true
false
TypeError

true

[] + [] + 'foo'.split('');

What is the result?

"f, o, o"
TypeError
["f", "o", "o"]
[][]["f", "o", "o"]

"f, o, o"

new Array(5).toString();

What is the result?

",,,,"
[]
"[]"

",,,,"

var myArr = ['foo', 'bar', 'baz'];
myArr.length = 0;
myArr.push('bin');
console.log(myArr);

What is printed in the console?

['foo', 'bar', 'baz']
['foo', 'bar', 'baz', 'bin']
['bin', 'foo', 'bar', 'baz']
['bin']

['bin']

String('Hello') === 'Hello';

What is the result?

true
false
TypeError

true

var x = 0;
function foo() {
    x++;
    this.x = x;
    return foo;
}
var bar = new new foo;
console.log(bar.x);

What is printed on the console?

ReferrenceError
TypeError
undefined
0
1

undefined

"This is a string" instanceof String;

What is the result?

true
false
TypeError

false

var bar = 1,
    foo = {};

foo: {
    bar: 2;
    baz: ++bar;
};
foo.baz + foo.bar + bar;

What is the result?

ReferenceError
TypeError
undefined
NaN
4
5

NaN

var myArr = ['foo', 'bar', 'baz'];
myArr[2];
console.log('2' in myArr);

What is the result of console.log?

true
false
ReferenceError

true

var arr = [];
arr[0]  = 'a';
arr[1]  = 'b';
arr.foo = 'c';
alert(arr.length);

What value is alerted?

1
2
3
undefined

10 > 9 > 8 === true;

What is the result?

true
false

false

function foo(a, b) {
    arguments[1] = 2;
    alert(b);
}
foo(1);

What value is alerted?

2
undefined
ReferenceError

undefined

NaN === NaN;

What is the result?

true
false
TypeError

false

What type of object system does JavaScript support?

Resources for this answer:

http://www.parrot.org/content/javascript-object-system

$(document).ready(function(){ $('.loader img').click(function() { $('.loader img').hide(); \\ $('.loader img').hide(); }); });

Are you sure you're ready for this Quiz ?

JavaScript Web Quiz By David Shariff

Full JavaScript

Windows Vista

Coming soon

Go to Start then select Connect To.
Wait a moment while your computer searches for all the wireless networks in range. Find somcablewifi from the list of available networks (SSIDs) and click it. Then click Connect.
You will be prompted that you are connecting to an unsecured wireless network. Click Connect Anyway.
Wait a few seconds while your computer acquires an IP address from the somcablewifi network.
The status will display as Connected, signifying you are connected to the somcablewifi network.

Also, the Wireless Network Connection icon will appear in your computer's system tray at the bottom of the screen near the clock. To display the strength of your connection, just hover over the icon with your mouse.

Once you've joined our somcable WiFi network manually, your device automatically joins it whenever the network is in range. If more than one previously-used network is in range, your device joins the one last used.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Due to the numerous WiFi devices and configurations available, Somcable is only able to confirm that SOMCABLE WiFi is functioning correctly. Somcable does not offer technical support for connecting devices to the Internet. Please refer to the user manual for your device should you require additional assistance.

Windows 7

Connect to the SOMCABLE WiFi Network

Open Connect to a Network by clicking the Start button, and then clicking Connect to.
In the Show list, click Wireless.
You'll see a list of the wireless networks currently available.
Click on somcablewifi, and then click Connect.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Mac OS X®

Make Sure WiFi Is Turned On

WiFi is used on Macs to set up and manage WiFi connections. The WiFi icon is found in the menu bar next to the clock.

If the icon is empty, WiFi is turned off, or you are not within WiFi range.

If the icon is filled in, you are currently within WiFi range.

To turn WiFi on

Click the WiFi icon.
Select Turn WiFi On.

Connect to the SOMCABLE WiFi Network

Click the WiFi icon.
Find somcablewifi from the list of available networks (SSIDs) and select it.
Wait a few moments while your Mac connects. Once connected, a check mark will appear in the WiFi menu next to the somcableywifi SSID.

Once you've joined our SOMCABLE WiFi network manually, your device automatically joins it whenever the network is in range. If more than one previously-used network is in range, your device will join the one last used.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

iPhone® or iPod touch®

Make sure WiFi is turned on

Tap Settings
Tap WiFi
Make sure WiFi is set to ON. If WiFi is set to OFF, tap the OFF button to turn it on.

Connect to the SOMCABLE WiFi Network

Once WiFi is turned on, it is easy to connect to SOMCABLE WiFi. From the iPhone or iPod Touch

Tap Settings
Tap WiFi
Wait a moment as your iPhone or iPod touch detects the WiFi networks in range
Find somcablewifi from the list of available networks (SSIDs) and tap it
Wait a few seconds while your iPhone or iPod touch connects. Once connected, a check mark will appear next to the somcablewifi SSID

Also, the WiFi icon will appear in your phone's status bar at the top of the screen when it is connected to a WiFi network. It will show connection strength as well. The more bars you see, the stronger your WiFi connection.

Once you've joined the SOMCABLE WiFi network manually, your iPhone or iPod touch will automatically connect whenever the network is in range of one of SOMCABLE WiFi hotspots. If more than one previously used network is in range, your device will join the one last used.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Blackberry®

Connect to the SOMCABLE WiFi Network

From the Blackberry home screen, select the Menu key
Roll the trackball to the icon for Set Up WiFi and click
Use the trackball to scroll down to the Next button and click.
Select Scan For Networks and click.
Scroll down to somcablewifi from the list of available networks (SSIDs) and click it. You'll see a message that your Blackberry is connecting to somcableywifi
Once your Blackberry connects to somcablewifi, you'll see "Connection Successful!" across the top of the screen. On this screen, you can save somcablewifi as a profile. Select Yes and click Next
Click Finish.

When you are connected, the WiFi logo across the top of your screen will turn black, and somcablewifi will display on the main screen below the clock.

Once you've joined the SOMCABLEWiFi network, your Blackberry will automatically connect to it whenever the network is in range.

Set the Browser to use WiFi

After you've connected to somcablewifi, you'll need to configure the Blackberry browser to use WiFi as the preferred Internet connection.

Launch the Blackberry's browser.
Press the Menu key to display the browser's menu
Select Options
Select General Properties
Click on the current setting for Default Browser and select WiFi Browser
Press the End button and confirm your choice by clicking Save

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or user name) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Setup WiFi as the Preferred Voice Connection

Some providers will allow you to use WiFi for voice service as well. This will enable you to make phone calls without using cellular plan minutes. Check with your cellular provider to see if this option is available with your plan.

If so, you can configure your Blackberry to use WiFi as the preferred voice connection. With this, your Blackberry will use your cellular provider's network only when WiFi is unavailable.

While on the Blackberry home screen, select the Menu key
Roll the trackball to the icon for Manage Connections and click
Scroll down to Mobile Network Options and click.
Select Connection Preference and click.
Select WiFi Preferred and click
Press the end button and confirm your choice by clicking Save

Technical Support

Windows Mobile 5/6

Note: Instructions may vary slightly from phone to phone as there are several different versions of Windows Mobile 5 and Windows Mobile. For details about your exact version, please consult your phone's documentation or visit http://www.microsoft.com/windowsmobile.

Enable WiFi on your Phone

Go to Start then Settings
Select Connections from the tabs across the bottom
Select Comm Manager

Important Note: On some phones, the Comm Manager is in the Programs folder. Simply go to Start then to Programs and select the Comm Manager icon.

Select the WiFi icon. When WiFi is activated, the icon fills in with green and the "x" mark disappears.

Connect to the SOMCABLE WiFi Network

Go to Start then Settings
Select Connections from the tabs across the bottom
Select Network Cards
Find somcablewifi from the list of available networks (SSIDs) and select and hold it. Then select Connect
In the next screen, make sure The Internet is selected and click OK
Wait a few seconds while your phone is connecting to the SOMCABLE WiFi network. Once complete, the status will display as Connected
Click OK from the top right section of the screen then close the Settings window with the x in the top-right section of the screen

Once you've joined the SOMCABLE WiFi network manually, your device automatically joins it whenever the network is in range. If more than one previously used network is in range, your device will join the one last used.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Android

Make sure WiFi is turned on

Note: Your service provider may charge to surf the Web or download data.

First, turn on your phone and start at the main screen
Next, click on the Settings icon
After that, press Wireless & networks followed by Wi-Fi settings
Now, touch Menu followed by Scan in order to find available networks in range
Next, touch somcablewifi to connect.
Finally, look for the wireless indicator icon to verify that your smartphone is connected

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

iPad®

Ensure WiFi is enabled

Tap Settings
Tap WiFi
Make sure WiFi is set to ON. If WiFi is set to OFF, tap the OFF button to turn it on.

Available WiFi networks appear under "Choose a Network".

Locate and tap somcablewifi.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Android

Ensure WiFi is enabled

Tap Apps in the upper right hand corner
Tap Setting
Tap Wireless & networks
Tap Wi-Fi – Turn on Wi-Fi.
Available WiFi networks appear under "Wi-Fi settings – Set up & manage wireless access points."
Locate and tap somcablewifi.

Sign In to SOMCABLE WiFi

Once you've connected to the somcablewifi network, simply launch your Web browser and you will be taken to the SOMCABLE WiFi login page.

Enter your Somcable.com email address (or username) and password
Click Sign In

After you successfully enter your credentials, you will be directed to the somcable.com home page. From there, you can begin to browse the Internet.

Technical Support

Due to the numerous WiFi devices and configurations available, Somcable is only able to confirm that WiFi is functioning correctly. Somcable does not offer technical support for connecting devices to the Internet. Please refer to the user manual for your device should you require additional assistance.

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JS Quiz Exercise Lab

(JS) JavaScript Interview Questions and Anwsers

JS Quiz Exercise Lab

Are you sure you're ready for this Quiz ?

JavaScript Web Quiz By David Shariff

Coming soon

Sign In to SOMCABLE WiFi

Technical Support

Connect to the SOMCABLE WiFi Network

Sign In to SOMCABLE WiFi

Technical Support

Make Sure WiFi Is Turned On

To turn WiFi on

Connect to the SOMCABLE WiFi Network

Sign In to SOMCABLE WiFi

Technical Support

Make sure WiFi is turned on

Connect to the SOMCABLE WiFi Network

Sign In to SOMCABLE WiFi

Technical Support

Connect to the SOMCABLE WiFi Network

Set the Browser to use WiFi

Sign In to SOMCABLE WiFi

Setup WiFi as the Preferred Voice Connection

Technical Support

Enable WiFi on your Phone

Connect to the SOMCABLE WiFi Network

Sign In to SOMCABLE WiFi

Technical Support

Make sure WiFi is turned on

Sign In to SOMCABLE WiFi

Technical Support

Ensure WiFi is enabled

Sign In to SOMCABLE WiFi

Technical Support

Ensure WiFi is enabled

Sign In to SOMCABLE WiFi

Technical Support

(JS) JavaScript
Interview Questions and Anwsers