A JavaScript function is executed when "something" invokes it (calls it). Example // Function to compute the product of p1 and p2 functionmyFunction(p1, p2) { returnp1 * p2; } Try it Yourself » JavaScript Function Syntax A JavaScript function is defined with thefunctionkeyword, followed...
console.log(square(5)); // 25 function square(n) { return n * n; } 尽管square() 函数在声明之前被调用,但此代码的运行并没有任何错误。这是因为 JavaScript 解释器会将整个函数声明提升到当前作用域的顶部,因此上面的代码等价于: jsCopy to Clipboard // 所有函数声明实际上都位于作用域的顶部 functi...
Function Declarations Earlier in this tutorial, you learned that functions aredeclaredwith the following syntax: functionfunctionName(parameters) { code to be executed } Declared functions are not executed immediately. They are "saved for later use", and will be executed later, when they are ...
50. Optional function parameters 51. Simplified function syntax 52. Boolean type 53. Predicates 54. Combination of logical expressions 55. Logical operators 56. Negation 57. Logical expressions output 58. Conditionals (`if`) 59. else 60. else if statement 61. Ternary operator 62. switch stateme...
JavaScript Constructor Function Parameters You can also create a constructor function with parameters. For example, // constructor function with parameters function Person (person_name, person_age, person_gender) { // assign parameter values to the calling object this.name = person_name, this.age ...
Here are a few examplesof basic syntax: // Two slashes start single-linecommentsvarx;// declaring a variablex=3+y;// assigning a value to the variable `x`foo(x,y);// calling function `foo` with parameters `x` and `y`obj.bar(3);// calling method `bar` of object `obj`// A...
The syntax of thecall()method is: func.call(thisArg, arg1, ... argN) Here,funcis a function. call() Parameters Thecall()method can taketwoparameters: thisArg- ThethisArgis the object that thethisobject references inside the functionfunc. ...
The following is the basic syntax of the function: function functionName(arg0, arg1,...,argN) { //表达式 } Below is an example: function sayHi(name, message) { console.log('Hello ' + name + ', ' + message) } The function can be called by the function name. The parameters to be...
letcalculator={// 对象字面量 新建对象operand1:1,operand2:1,add(){// We're using method shorthand syntax for this function// Note the use of the this keyword to refer to the containing object.this.result=this.operand1+this.operand2;}};calculator.add();// A method invocation to compute...
// Defining function `baz` with parameters `a` and `b` function baz(a, b) { return a + b; } 注意等号的两种不同用法: 单个等号(=)用于将一个值赋给一个变量。 三个等号(===)用于比较两个值(参见相等运算符)。 注释 有两种注释: ...