// Global variable referenced by following function. // If we had another function that used this name, now it'd be an array and it could break it. var name = 'Ryan McDermott'; function splitIntoFirstAndLastName() { name = name.split(' '); } splitIntoFirstAndLastName(); console....
// 变量名严格区分大小写varname="Tom";varName="Jerry";console.log("name : "+name+" , Name : "+Name); 浏览器控制台输出结果如下 : 4、变量不能是 关键字 JavaScript 变量名 不能是 JavaScript 语言 的 保留字 或 关键字 , 如var、function、let、const等关键字 ; 下面 使用var关键字作为变量名...
classRectangle{constructor(width, height){this.width= width;this.height= height; }staticdisplayName ='Rectangle';staticgetArea(){returnthis.width*this.height; } }constsquare1 =newRectangle(40,20);console.log(square1.displayName);//undefinedconstsquare2 =newRectangle(60,30);console.log(square2....
Because both function1 and function2 depend on the global variable global, running these functions in parallel causes undesirable effects. Now change these functions into a pure function as explained in Listing 1-11.let function1 = (input,global) => { // works on input //changes global globa...
var $name = "Tom"; 1. 2. 3. 4. 数字 不能 作为 变量名 的开头 An identifier or keyword cannot immediately follow a numeric literal.javascript 1. 代码示例 : <!DOCTYPE html> <!-- 设置 meta 视口标签 --> JavaScript<
functionname(parameter1, parameter2, parameter3) { //code to be executed } Functionparametersare listed inside the parentheses () in the function definition. Functionargumentsare thevaluesreceived by the function when it is invoked. Inside the function, the arguments (the parameters) behave as loc...
In the above example, we passed "John" as an argument to the greet() function. Pass Argument to the Function Notice the name variable declared inside parentheses: function greet(name) { // code } Here, name is a function parameter, which acts as a placeholder to store the function argu...
Function scope # If you declare a local variable inside a function with the exact same name as a global variable, then the local variable will hide the global variable. In the next example, the local client variable hides the global client variable. copy var client = "Joan"; // global...
So, the variable names msg, MSG, Msg, mSg are considered separate variables. Variable names can contain letters, digits, or the symbols $ and _. A variable name cannot start with a digit 0-9. A variable name cannot be a reserved keyword in JavaScript, e.g. var, function, return ...
In the JavaScript library jQuery, for instance, the main function$is used to select HTML elements. In jQuery$("p");means "select all p elements". JavaScript Underscore (_) Since JavaScript treats underscore as a letter, identifiers containing _ are valid variable names: ...