Web Development Basics Quiz

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Questions and Answers

Which of the following are considered front-end languages?

JavaScript (correct)

Java

CSS (correct)

HTML (correct)

What does URL stand for?

Uniform Resource Locator

A domain name is a unique name for a web site.

True

Which of these is NOT a method for HTTP requests?

OPTION Signup and view all the answers

The protocol used for secured communication over the web is called ______.

HTTPS Signup and view all the answers

Which HTML tag is used to define headings?

<h1> Signup and view all the answers

What is the purpose of the alt attribute in an image tag?

To provide alternate text for the image Signup and view all the answers

Which of the following best describes what JavaScript is?

A programming language Signup and view all the answers

Match the following HTML elements with their descriptions:

= Defines a paragraph <img> = Defines an image <a> = Defines a hyperlink <h1> = Defines a top heading Signup and view all the answers

What is the purpose of using comments in JavaScript?

To aid in code documentation and debugging Signup and view all the answers

The language in which JavaScript is primarily written is called ______.

JavaScript Signup and view all the answers

JavaScript is case sensitive.

True Signup and view all the answers

What does the following JavaScript statement do? `document.getElementById("demo").innerHTML = "Hi, Everyone."`

It writes 'Hi, Everyone.' inside an HTML element with id='demo'. Signup and view all the answers

Semicolons in JavaScript are optional at the end of statements.

False Signup and view all the answers

Which of the following characters can be used to start a JavaScript variable name?

An underscore (_) Signup and view all the answers

What does the assignment operator `=` do in JavaScript?

It assigns a value to a variable. Signup and view all the answers

What happens if you declare a variable without assigning a value?

The variable will have the value undefined. Signup and view all the answers

What is the significance of the `function` keyword in JavaScript?

It defines a block of code that can be executed when invoked. Signup and view all the answers

How are JavaScript strings written?

Strings are written inside single or double quotes. Signup and view all the answers

The length of a string is found in the property ______.

length Signup and view all the answers

Which of the following is a correct way to define a JavaScript variable?

var myVariable = 30; Signup and view all the answers

JavaScript variables are case sensitive.

True Signup and view all the answers

What does the `new` keyword do when defining a string in JavaScript?

Creates a string as an object. Signup and view all the answers

What do arrays use for indexes?

Numbered indexes Signup and view all the answers

What do objects use for indexes?

Named indexes Signup and view all the answers

When should you use objects?

When element names are strings Signup and view all the answers

Which of the following is a bad way to create an array?

var points = new Array(1, 2, 3); Signup and view all the answers

How can you check if a variable is an array?

Using the isArray() function Signup and view all the answers

The `pop()` method removes the last element from an _____.

array Signup and view all the answers

What does the `push()` method do?

Adds a new element to the end of an array Signup and view all the answers

What method would you use to sort an array alphabetically?

sort() Signup and view all the answers

What does the `reverse()` method do?

Reverses the order of the elements in an array Signup and view all the answers

What is returned if you compare two equal values using `===`?

true Signup and view all the answers

When is the `splice()` method used?

Both A and B Signup and view all the answers

What is the maximum number of decimal places in JavaScript?

17 Signup and view all the answers

The result of `0.2 + 0.1` in JavaScript is approximately ______.

0.30000000000000004 Signup and view all the answers

What will the value of `y` be after executing `var y = 9999999999999999;`?

10000000000000000 Signup and view all the answers

Division by zero in JavaScript results in NaN.

False Signup and view all the answers

Which function is used to check if a value is NaN in JavaScript?

isNaN() Signup and view all the answers

What keyword is used to create a number object in JavaScript?

new Number Signup and view all the answers

What does `typeof Infinity` return?

number Signup and view all the answers

What are the three JavaScript functions used for converting variables to numbers?

Number(), parseInt(), parseFloat() Signup and view all the answers

Which Math method rounds a number to the nearest integer?

Math.round() Signup and view all the answers

JavaScript arrays can hold different types of elements.

True Signup and view all the answers

Which method can be used to get the length of an array?

length Signup and view all the answers

The ISO date format in JavaScript is represented as ______.

YYYY-MM-DD Signup and view all the answers

What method converts a date to a UTC string in JavaScript?

toUTCString() Signup and view all the answers

How do you create a new date object for January 1, 1970?

All of the above Signup and view all the answers

What does the `getFullYear()` method do?

Get the full year as a four-digit number Signup and view all the answers

JavaScript supports associative arrays.

False Signup and view all the answers

Study Notes

Front End Languages

HTML, CSS, and JavaScript are the “front end languages” that are used to build web pages and applications.

Front End Development

Front end development is not design.
It is the process of creating HTML, CSS, and JavaScript for a user interface, based on designs from designers.

URL

URL stands for Uniform Resource Locator.
It is the address of a resource on the internet.
It includes the protocol, domain name, and file or resource name.
Dynamic URLs include additional parameters in a key=value pair format that can be used to provide unique content or to pass information between client and server.
URL encoding is used to convert non-ASCII characters into a valid ASCII format using a percent sign followed by two hexadecimal digits.

HTTP

HTTP stands for Hypertext Transfer Protocol.
It is a protocol used to communicate between a client and server over the web.
Two common methods for requests are GET and POST.
GET requests data from a resource and has limited length.
POST submits data to be processed to a resource and has no data limit.

HTTPS

HTTPS is Hypertext Transfer Protocol Secure.
It is a secure version of HTTP where all communication is encrypted and authenticated using SSL.

Web Server

A web server is a program that serves files that form web pages to users in response to their requests.

Application Server

An application server is a software framework that allows the creation and running of web applications.

Web Services

Web services are applications that communicate over the web using HTTP and communicate using XML messages.

Web Agents / User Agents

These are software applications used by users to communicate with the web server, such as web browsers.

Domain

A domain name is a unique name for a website, such as google.com or facebook.com.
The domain name is mapped to an IP address, which represents a physical location on the internet.
A domain name consists of a Top Level Domain (TLD), Second Level Domain, and optionally a Third Level Domain or subdomain.

Hosting

Internet hosting services run internet servers that allow organizations and individuals to serve content on the web.

FTP

FTP stands for File Transfer Protocol.
It is a standard network protocol used to transfer files between hosts over a TCP-based network.
Files are split into small data packets and transmitted over an authenticated connection.

FTP Client

An FTP client is software that allows users to communicate with an FTP server to transfer files.

HTML

HTML stands for Hyper Text Markup Language.
It is the standard markup language used to create web pages.
Web browsers can read HTML files and render them into visible or audible web pages.

HTML Documents

HTML documents must start with a type declaration: <!DOCTYPE html>.
The document itself begins with <html> and ends with </html>.
The visible part of the HTML document is between <body> and </body>.

HTML Headings

HTML headings are defined with <h1> to <h6> tags.

HTML Paragraphs

HTML paragraphs are defined with  tag.

HTML Images

HTML images are defined with the <img> tag.
The src attribute specifies the source file, alt specifies alternative text, and width and height specify the size.

HTML Elements

HTML elements are written with a start tag, end tag, and content in between.
All HTML documents consist of nested HTML elements.

HTML Attributes

HTML elements can have attributes that provide additional information about the element.
Attributes are specified in the start tag and are in name/value pairs.

Lang Attribute

The lang attribute in the <html> tag declares the document language, which is important for accessibility and search engines.

Title Attribute

The title attribute provides a short description of the element or content.

Href Attribute

The href attribute is used in the <a> tag to define the target URL or destination of the link.

Alt Attribute

The alt attribute is used with the <img> tag to provide alternative text for images that cannot be displayed.
Screen readers use the alt text to describe images to users.

Image Size: Width and Height

You can use the width and height attributes in the <img> tag to define the dimensions of an image.

JavaScript Programs

JavaScript programs are a series of instructions executed by the computer.
In JavaScript, these instructions are called statements and are separated by semicolons.

JavaScript Statements

Statements are composed of values, operators, expressions, keywords, and comments.
JavaScript ignores spaces and line breaks, but uses semicolons to separate statements.

JavaScript Values

JavaScript has two types of values:
- literals: fixed values such as numbers or strings.
- variables: values that can be changed.

JavaScript Literals

Numbers are written with or without decimals.
Strings are text written within double or single quotes.

JavaScript Variables

Variables are used to store data values.
The var keyword is used to define variables.
Values are assigned to variables using an equal sign.

JavaScript Operators

The assignment operator (=) assigns values to variables.
Arithmetic operators (+ , - , * , /) are used to perform calculations.

JavaScript Keywords

Keywords identify actions to be performed.
The var keyword creates a new variable.

JavaScript Comments

Comments are used to explain code and make it more readable.
Single-line comments start with //.
Multi-line comments start with /* and end with */.

JavaScript Case Sensitivity

JavaScript identifiers are case-sensitive, so lastName and lastname are different variables.

JavaScript Character Set

JavaScript uses the Unicode character set, which covers all the characters, punctuations, and symbols in the world.

JavaScript Code Blocks

JavaScript statements can be grouped together in code blocks, which are enclosed in curly brackets ({...}).
Code blocks are used to define statements that are executed together.

Comments

Using comments to prevent execution of code is beneficial for code testing
The // symbol in front of a code line turns it into a comment, preventing execution

JavaScript Variables

JavaScript variables are used to store data values.
In the example: var x = 5;, x holds the value 5.
Identifiers are unique names given to variables, following these rules:
- Can contain letters, digits, underscores, and dollar signs
- Must start with a letter or $ and _
- Case sensitive (y and Y are different variables)
- Cannot use reserved words (JavaScript keywords) as names
= (equal sign) is an assignment operator, not an "equal to" operator in JavaScript.
JavaScript variables can hold numbers (like 100) and text values (called strings, like "John Doe").
Strings are written inside double or single quotes. Numbers are written without quotes.
Declaring a variable in JavaScript is called "declaring."
Use the var keyword followed by the variable name to declare a variable: var carName;
Assign a value to a declared variable using the equal sign: carName = "Volvo";
Multiple variables can be declared in one statement: var person = "John Doe", carName = "Volvo", price = 200;
Variables declared without a value will have the value undefined: var carName;
Re-declaring a JavaScript variable will not remove its value.

JavaScript Operators

Arithmetic operations can be performed with JavaScript variables using operators like = and +.
The + operator is also used to concatenate (add) strings.
Adding a number and a string returns a string.

JavaScript Functions

A JavaScript function is a block of code designed to perform a specific task.
Functions are invoked (executed) when "something" calls them.
Function syntax: function name(parameter1, parameter2, parameter3) { code to be executed }
Parameters are listed in the function definition. Arguments are the actual values passed when invoking the function.
Functions can be called by:
- Events (e.g., user clicks a button)
- JavaScript code (e.g., calling the function directly)
- Automatically (self-invoked)
The return statement stops function execution and returns a value to the invoking statement.
Functions are important as they allow code reuse and flexibility.
Invoking a function uses the () operator: toCelsius(32)
Accessing a function without () returns the function definition: toCelsius
Functions can be used as variables, like: var text = "The temperature is " + toCelsius(32) + " Centigrade";

JavaScript Objects

JavaScript objects are containers for named values called properties and methods.
Properties can be primitive values, other objects, or functions.
An object method is an object property containing a function definition.

JavaScript Scope

Scope determines the accessibility of variables, objects, and functions.
JavaScript has function scope: The scope changes within functions.
Local variables (declared within a function) are only accessible inside that function.
Global variables (declared outside a function) are accessible from anywhere on the webpage.
Assigning a value to an undeclared variable automatically makes it global.
The lifetime of a variable:
- Local variables are deleted when the function ends.
- Global variables are deleted when the page closes.
- Function arguments act as local variables inside functions.
- In HTML, the global scope belongs to the window object.

JavaScript Events

Events are actions triggered by the user or browser (e.g., page loading, input field change, button click).
JavaScript can execute code when these events occur.
HTML elements can have event handler attributes (e.g., onclick) with JavaScript code.

JavaScript Strings

A JavaScript string is a sequence of characters (like "Mike Slough").
Strings can be enclosed in single or double quotes.
Quotes can be used inside a string as long as they don't match the surrounding quotes.
length is a built-in property to determine the string's length.
Escape character (\) is used to include special characters in strings: var y = "We are the so-called \"Vikings\" from the north.“
Break up long code lines after operators or use string addition for readability.
Strings can be primitive values or objects (created with new String).
- == (equality operator) considers strings with equal values as equal.
- === (strict equality operator) requires both the type and value to be equal.
Strings have properties and methods, even primitive values.

JavaScript Numbers

JavaScript numbers can be written with or without decimals.
Extra large or small numbers can be represented using scientific notation (exponent).
JavaScript numbers are always 64-bit floating-point numbers, based on the IEEE 754 standard.
Integer values are typically accurate up to 15 digits.
Floating-point arithmetic might have slight inaccuracies due to the format.
Hexadecimal numbers are written with 0x prefix: var x = 0xFF;
Infinity is returned for calculations exceeding the maximum number or division by 0.
- Type of Infinity is number.
NaN (Not a Number) represents invalid arithmetic operations.
- Use isNaN() function to check if a value is NaN.
Numbers can be primitive values or objects (new Number()).
- == considers numbers with equal values as equal.
- === requires both type and value equality.
Numbers have properties and methods even though they are primitive values.

JavaScript Number Methods

JavaScript number methods are used to manipulate and transform numbers.
They return new values without affecting the original variable.
Some examples:
- toString(): Returns a number as a string.
- toExponential(): Rounds a number and returns it in exponential notation.
- toFixed(): Rounds and returns a string with a specified number of decimals.
- toPrecision(): Returns a string with a specified number of digits (including decimals).
- valueOf(): Returns a number as a number.

Converting Variables to Numbers

These three global JavaScript methods can convert variables to numbers:
- Number(): Converts variables to numbers.
- parseInt(): Converts a string to an integer.
- parseFloat(): Converts a string to a floating-point number.

Number

The Number() function converts a value to a number.
true converts to 1.
false converts to 0.
new Date() converts to a timestamp representing milliseconds since January 1, 1970.
"10" converts to 10 but "10 20" returns NaN (Not a Number).

parseInt()

Parses a string and returns an integer.
Spaces are allowed within the string.
Only returns the first number encountered.
Returns NaN it cannot be converted to an integer.
parseInt("10") returns 10
parseInt("10.33") returns 10
parseInt("10 20 30") returns 10
parseInt("10 years") returns 10
parseInt("years 10") returns NaN

parseFloat()

Parses a string and returns a number.
Spaces are allowed within the string.
Only returns the first number encountered.
Returns NaN if it cannot be converted to a number.
parseFloat("10") returns 10
parseFloat("10.33") returns 10.33
parseFloat("10 20 30") returns 10
parseFloat("10 years") returns 10
parseFloat("years 10") returns NaN

Math Object

The Math object contains useful mathematical methods and constants.
Math.random() returns a random number between 0 and 1.
Math.min() and Math.max() find the minimum or maximum values from a list of arguments.

Math Object Methods

Math.round() rounds a number to the nearest integer.
Math.ceil() rounds a number up to the nearest integer.
Math.floor() rounds a number down to the nearest integer.

Math Object Constants

Math.E returns Euler's number.
Math.PI returns PI.
Math.SQRT2 returns the square root of 2.
Math.SQRT1_2 returns the square root of 1/2.
Math.LN2 returns the natural logarithm of 2.
Math.LN10 returns the natural logarithm of 10.
Math.LOG2E returns base 2 logarithm of E.
Math.LOG10E returns base 10 logarithm of E.

Date Object

The Date object is used to work with dates.
Dates can be represented as strings or numbers.
A Date object represented as a number is the number of milliseconds since January 1, 1970, 00:00:00.

Displaying Dates

You can display a date using Date() within a innerHTML statement.

Creating Date Objects

You can create a Date object using the new Date() constructor.
new Date() creates a Date object representing the current date and time.
new Date(milliseconds) creates a Date object based on a timestamp (milliseconds since January 1, 1970).
new Date(dateString) creates a Date object based on a valid date string.
new Date(year, month, day, hours, minutes, seconds, milliseconds) creates a Date object with the specified date and time.

Date Methods

toString() returns a string representation of a Date object.
toUTCString() returns a UTC string representation of a Date object.
toDateString() returns a more readable string representation of a Date object.

Date Formats

There are three main date formats:
- ISO Dates: YYYY-MM-DD
- Long Dates: MMM DD YYYY (month can be written fully or abbreviated)
- Short Dates: MM/DD/YYYY or MM-DD-YYYY

Date Get Methods

getDate() returns the day of the month (1-31).
getDay() returns the day of the week (0-6).
getFullYear() returns the four-digit year.
getHours() returns the hour (0-23).
getMilliseconds() returns the milliseconds (0-999).
getMinutes() returns the minutes (0-59).

Date Set Methods

setDate() sets the day of the month.
setFullYear() sets the year (optionally the month and day).
setHours() sets the hour.
setMilliseconds() sets the milliseconds.

Adding Days to a Date

You can add days to a Date object using setDate(getDate() + days).

Converting a String to a Date

Date.parse() converts a valid date string to milliseconds since January 1, 1970.
You can create a Date object using the milliseconds returned by Date.parse().

Comparing Dates

You can compare Date objects using standard comparison operators (>, <, >=, <=).

Arrays

An array is a special variable that can hold multiple values.
Array elements are accessed using index numbers (starting from 0).

Creating Arrays

You can create an array using an array literal:
- var arrayName = [item1, item2, ...].
You can also create an array using the new Array() constructor.

Accessing Array elements

You access array elements by their index number.

Array Properties and Methods

length property: Returns the number of elements in the array.
sort() method: Sorts array elements alphabetically.
reverse() method: Reverses the order of elements in an array.

Adding Array Elements

Use fruits[fruits.length] = "Lemon"; to add an element at the end.
push() method adds an element at the end of the array.

Removing Array Elements

pop() method removes the last element from the array.
shift() method removes the first element from the array.

Changing Array Elements

You can change an element by assigning a new value to the index.

Deleting Array Elements

Use delete operator.

Splicing an Array

splice() method allows adding or removing elements at a specific index.

Array Methods for String Conversion

valueOf() returns a comma separated string representation of the array.
toString() returns the same as valueOf().

Sorting Arrays using the Compare Function

sort() method can use a compare function to specify a custom sorting order.
The compare function should return a negative, zero, or positive value, based on the comparison of two elements.
The sort method uses the compare function's return value to determine the sorting order.

Associative Arrays

JavaScript does not support associative arrays (arrays with named indexes).

Differences Between Arrays and Objects

Arrays use numbered indexes.
Objects use named indexes.
You should use objects where the element names are strings (text).
You should use arrays where the element names are numbers.

Good Practices for Arrays

Use the array literal [] to create arrays instead of new Array().
Use the built-in isArray() function to check if a variable is an array.

Array Methods

pop() method removes the last element from an array.
push() method adds a new element to the end of an array.
shift() removes the first element from an array.
splice() method removes or adds elements at a specific index.
sort() method sorts the elements of an array alphabetically.
reverse() method reverses the order of elements in an array.
The sort() method can use a compare function to define a custom sorting order.

JavaScript Functions

When calculating the difference between 40 and 100, the function returns a negative value of -60
The sort function prioritizes lower values, so 40 will be sorted before 100
Joining arrays is done by combining two arrays
The concat() method joins arrays
For example:
- myGirls array contains "Aisha" and "Meryam"
- myBoys array contains "Bilal", "Umer", and "Ali"
- myChildren array is created using the myGirls.concat(myBoys) method

Slicing Arrays

The slice() method extracts a portion of an array, creating a new array
For example:
- the fruits array contains "Banana", "Orange", "Lemon", "Apple", and "Mango"
- the citrus array is created with the fruits.slice(1, 3) method and contains "Orange" and "Lemon", indicating extraction from the first to the third element
- the citrus array is created with the fruits.slice(2) method and contains "Lemon", "Apple", and "Mango", indicating extraction from the second element to the end

JavaScript Comparisons

Comparison operators are used to determine if variables or values are equal or different
The operators are used within logical statements
Example of comparison operators and results for x=5:
- == operator checks for equality. Returns true if both sides are equal, false otherwise.
- === operator checks for equality in both value and type. Returns true if both sides are equal in both, false otherwise.
- != operator checks for inequality, returns true if both sides are not equal, false otherwise.
- !== operator checks for inequality in either value or type, returns true if both sides are not equal, false otherwise.
- operator checks if the left side is greater than the right side, returns true if it is, false otherwise.
- < operator checks if the left side is less than the right side, returns true if it is, false otherwise.
- = operator checks if the left side is greater than or equal to the right side, returns true if it is, false otherwise.
- <= operator checks if the left side is less than or equal to the right side, returns true if it is, false otherwise.

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Description

Test your knowledge on front-end languages, HTML, and JavaScript essentials. This quiz covers basic concepts such as HTML tags, HTTP requests, and the purpose of various attributes. Perfect for beginners looking to solidify their understanding of web development fundamentals.

Web Development Basics Quiz

Podcast Beta

Questions and Answers

Which of the following are considered front-end languages?

What does URL stand for?

A domain name is a unique name for a web site.

Which of these is NOT a method for HTTP requests?

The protocol used for secured communication over the web is called ______.

Which HTML tag is used to define headings?

What is the purpose of the alt attribute in an image tag?

Which of the following best describes what JavaScript is?

Match the following HTML elements with their descriptions:

What is the purpose of using comments in JavaScript?

The language in which JavaScript is primarily written is called ______.

JavaScript is case sensitive.

What does the following JavaScript statement do? document.getElementById("demo").innerHTML = "Hi, Everyone."

Semicolons in JavaScript are optional at the end of statements.

Which of the following characters can be used to start a JavaScript variable name?

What does the assignment operator = do in JavaScript?

What happens if you declare a variable without assigning a value?

What is the significance of the function keyword in JavaScript?

How are JavaScript strings written?

The length of a string is found in the property ______.

Which of the following is a correct way to define a JavaScript variable?

JavaScript variables are case sensitive.

What does the new keyword do when defining a string in JavaScript?

What do arrays use for indexes?

What do objects use for indexes?

When should you use objects?

Which of the following is a bad way to create an array?

How can you check if a variable is an array?

The pop() method removes the last element from an _____.

What does the push() method do?

What method would you use to sort an array alphabetically?

What does the reverse() method do?

What is returned if you compare two equal values using ===?

When is the splice() method used?

What is the maximum number of decimal places in JavaScript?

The result of 0.2 + 0.1 in JavaScript is approximately ______.

What will the value of y be after executing var y = 9999999999999999;?

Division by zero in JavaScript results in NaN.

Which function is used to check if a value is NaN in JavaScript?

What keyword is used to create a number object in JavaScript?

What does typeof Infinity return?

What are the three JavaScript functions used for converting variables to numbers?

Which Math method rounds a number to the nearest integer?

JavaScript arrays can hold different types of elements.

Which method can be used to get the length of an array?

The ISO date format in JavaScript is represented as ______.

What method converts a date to a UTC string in JavaScript?

How do you create a new date object for January 1, 1970?

What does the getFullYear() method do?

JavaScript supports associative arrays.

Study Notes

Front End Languages

Front End Development

URL

HTTP

HTTPS

Web Server

Application Server

Web Services

Web Agents / User Agents

Domain

Hosting

FTP

FTP Client

HTML

HTML Documents

HTML Headings

HTML Paragraphs

HTML Images

HTML Elements

HTML Attributes

Lang Attribute

Title Attribute

Href Attribute

Alt Attribute

Image Size: Width and Height

JavaScript Programs

What does the following JavaScript statement do? `document.getElementById("demo").innerHTML = "Hi, Everyone."`

What does the assignment operator `=` do in JavaScript?

What is the significance of the `function` keyword in JavaScript?

What does the `new` keyword do when defining a string in JavaScript?

The `pop()` method removes the last element from an _____.

What does the `push()` method do?

What does the `reverse()` method do?

What is returned if you compare two equal values using `===`?

When is the `splice()` method used?

The result of `0.2 + 0.1` in JavaScript is approximately ______.

What will the value of `y` be after executing `var y = 9999999999999999;`?

What does `typeof Infinity` return?

What does the `getFullYear()` method do?