JavaScript Summary

JavaScript is an essential programming language in web development, often referred to as the brain of web pages.

Let's briefly summarize the core concepts of JavaScript.

Containers for storing data. Stored data can be of various types such as numbers, strings, booleans, objects, etc.

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let name = 'CodeFriends';

Reusable blocks of code that perform specific tasks.

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function greet(userName) {
  console.log('Hello, ' + userName + '!');
}

greet('CodeFriends'); // "Hello, CodeFriends!" output

Execute different code based on certain conditions.

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if (name === 'CodeFriends') {
  console.log('Hello, CodeFriends!');
} else {
  console.log('Hello, Guest!');
}

Repeat a block of code multiple times based on certain conditions.

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for (let i = 0; i < 5; i++) {
  console.log(i); // Outputs 0 to 4
}

Collections of related data and/or functionality. These are often referred to as properties (keys).

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const person = {
  name: 'CodeFriends', // name property, string value
  age: 25, // age property, number value
  greet: function () { // greet property, function value
    console.log('Hello, ' + this.name + '!');
  },
};

person.greet(); // "Hello, CodeFriends!" output

Interactions on a web page such as button clicks, form submissions, page loads, etc.

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let button = document.querySelector('button');

// Button click event listener
button.addEventListener('click', function () {
  alert('You clicked the button!');
});