Learn about JavaScript in Apple Chrome

With the continuous development of Internet technology, Web programming is becoming more and more popular and important. As one of the most commonly used scripting languages ​​in front-end development, JavaScript has played an increasingly important role in Web development. For Apple browser, its built-in JavaScript engine is JavaScriptCore. Let us learn about the relevant knowledge of Apple browser JavaScript.

1. Introduction to JavaScript

JavaScript is one of the most widely used scripting languages. It was jointly developed by Netscape and Sun Microsystems. It was originally called LiveScript and was later renamed JavaScript. People call it JS. JavaScript is a prototype-based language that borrows many syntax and concepts from the C language, but is not an extension of the C language. JavaScript is an interpreted language that can run on the browser side and Node.js server side. It can be called and executed through HTML pages and external files (.js files).

2. JavaScript engine of Apple browser

The JavaScript engine used by Safari is JavaScriptCore. JavaScriptCore is a JavaScript engine developed by Apple. It is open source and is used for Safari browsing. devices, iCloud and other Apple’s own products. It is one of the components built on WebKit (Web Rendering Engine), which is an open source web browser engine and a rendering engine developed by Apple for Mac OS X, iPhone, iPad, etc.

3. Basic Usage of Apple Browser JavaScript

The Apple Browser JavaScript engine provides many powerful objects and functions that allow us to develop Web pages and applications quickly and flexibly. Some common basic usages and examples are listed below:

1. Variable declaration and assignment

JavaScript variables use the var keyword for declaration and assignment, and can store any type The data. When declaring, you can assign a value directly or leave it blank, as shown below:

var num = 100; //Declare an integer variable and assign it a value of 100
var str = 'Hello World!'; // Declare a string variable and assign the value to 'Hello World!'
var myArray = []; //Declare an empty array variable
var myObj = {}; //Declare an empty object variable

2. Conditional statements

The most commonly used conditional statements in JavaScript are if, else if and else, which can perform different operations according to different conditions, as shown below:

var num = 100;
if(num > 0){
console.log('num is greater than 0');
}else if(num < 0){
console.log( 'num is less than 0');
}else{
console.log('num is equal to 0');
}

3. Loop statement

The most commonly used loop statements in JavaScript are for, while and do while, which can repeatedly execute a set of statements, as shown below:

for(var i = 0; i < 10; i ){
console.log(i);
}
var i = 0;
while(i < 10){
console.log(i);
i ;
}
var i = 0;
do{
console.log(i);
i ;
}while(i < 10);

4. Function Defining and calling

A function in JavaScript is a reusable block of code that can receive parameters and return a value. You can define a function using the function keyword and call it using the function name, as follows:

function add(x, y){
return x y;
}
var result = add(1, 2); //The value of result is 3

5. Summary

JavaScriptCore, the built-in JavaScript engine of Safari, is a very powerful tool that provides a wealth of The objects and functions can meet our various web development needs. Understanding the basic syntax and common usage of JavaScript can help us better develop programs and solve problems.

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