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JavaScript Easy

What is the difference between =, == & === ?

single equals to (=)

= Single equal to is a Assignment Operator. If you want to assign the value of variable then use single equal to.

Example :

let Num = 20;
console.log(Num);

Output

20

double equals to (==)

== Double equal to is a Comparison Operator. And for comparing two value of variable using comparison operator and then output will show in boolean format (true or false).

Example 2

let num1 = 10;
let num2 = 10;
document.write(num1 == num2);

Output

true

tripple equals to (===)

=== Tripple equal to Also known as strict equality operator, it compares both the value and then output will show in boolean format (true or false).

Example 3

let num1 = 10;
let num2 = 10;
document.write(num1 === num2);

Output

true

What is Template String in Javascript?

Template String is a another way to create a String in javaScript to embedded a variables and expression in javaScript .
It denoted as a backticks (``) character instead of double " " or single quotes ' ' and It allows placeholder ${ } to embedded variables and expression directly .
Template string is used to string formating .
With the help of Template string we can add multiline String without using Escape character \n

<!DOCTYPE html>
<html>
<head>
</head>
<body>
  <script>
    const num1 = 80;
    const num2 = 20;
    console.log(`The sum of ${num1} and ${num2} is `${num1+num2});
  </script>
</body>
</html>

output:

The sum of 80 and 20 is 100.

In above example In Line no. 7 we create one variable num1 and store 80 ,In Line no. 8 create a variable num2 and store a value 20 and In Line no. 9 In console.log() we print a actual value of num1 and num2 and it sum with the help of ${}.

What are the events in JavaScript?

An event in JavaScript is basically something that happens when a user interacts with a webpage. It could be clicking a button, moving the mouse , or pressing a key. For example, when you press the "tab" key and a text box changes on a webpage, that's an event.

JavaScript has several built-in event objects.

onclick():The onclick event in Javascript occurs when the user clicks on an element.

For Example

<button onclick="alert('Call onClick Event')">Click Me</button>

ondblclick():This event occurs when the user double-clicks on an element.

onchange(): This event occurs when the value of an input field, select option, or textarea is changed.

onkeypress():This event occurs when the user presses a key down over an element.

onkeyDown():This event occurs when the user presses a key down over an element.

onkeyUp():This event occurs when the user releases a key which was pressed over an element.

onmouseover():This event occurs when the mouse pointer enters the active area of an element.

onMouseMove():This event occurs when the user moves the mouse over an element.

onmouseout():This event occurs when the mouse pointer exits the active area of an element.

onload():This event occurs when HTML document has finished loading.

Difference between setTimeout() and setInterval()?

Both setTimeout() and setInterval() are JavaScript functions used to delay the execution of code. They both allow you to specify a delay, which is the time you want to wait before the code is executed.

In setTimeout(), you provide a function that will be executed after a specified delay, but only once. After the function finishes executing

Syntax: setTimeout(function, delay)

setTimeout(function () {
  console.log("This code runs after a delay");
}, 1000); // Executes after 1000 milliseconds (1 second)

In setInterval() is used to repeatedly execute a specified function or code snippet at defined intervals.

Syntax: setInterval(function, delay)

setInterval(function () {
  console.log("This code runs repeatedly at a specified interval");
}, 2000); // Executes every 2000 milliseconds (2 seconds)

JavaScript Easy​

JavaScript Easy