JavaScript is a versatile programming language used primarily for web development;
Breakdown of the basic JavaScript syntax, structure, and layout.
1. Comments:
- Single-line comments start with `//`.
- Multi-line comments are enclosed between `/` and `/`.
// This is a single-line comment
/*
This is a
multi-line
comment
*/
2. Variables:
- Declared using `var`, `let`, or `const`.
- `var` is function-scoped, while `let` and `const` are block-scoped.
- `let` allows reassignment, while `const` creates a constant whose value cannot be changed once defined.
var x = 5;
let y = 10;
const z = 15;
3. Data Types:
- JavaScript has several data types, including numbers, strings, booleans, arrays, objects, etc.
let num = 10;
let str = "Hello";
let bool = true;
let arr = [1, 2, 3];
let obj = { name: "John", age: 30 };
4. Operators:
- Arithmetic operators (`+`, `-`, `*`, `/`, `%`).
- Comparison operators (`==`, `===`, `!=`, `!==`, `>`, `<`, `>=`, `<=`).
- Logical operators (`&&`, `||`, `!`).
let sum = 5 + 3;
let isEqual = (sum === 8);
let isGreater = (sum > 5);
5. Control Structures:
- Conditional statements (if-else).
- Loops (for, while, do-while).
if (condition) {
// Code block to execute if condition is true
} else {
// Code block to execute if condition is false
}
for (let i = 0; i < 5; i++) {
// Code block to execute repeatedly
}
while (condition) {
// Code block to execute while condition is true
}
6. Functions:
- Functions are blocks of code that perform a specific task.
- They can be declared or expressed.
// Function declaration
function greet(name) {
return "Hello, " + name + "!";
}
// Function expression
let greet = function(name) {
return "Hello, " + name + "!";
};
7. Objects and Classes:
- Objects are collections of key-value pairs.
- Classes allow you to create objects with shared properties and methods.
// Object
let person = {
name: "John",
age: 30,
greet: function() {
return "Hello, my name is " + this.name + "!";
}
};
// Class
class Person {
constructor(name, age) {
this.name = name;
this.age = age;
}
greet() {
return "Hello, my name is " + this.name + "!";
}
}
Things to Try
• Create a single html file with a script - write a small program that demonstrates each of the '7' basic syntax, structure, and layout points discussed above.
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