使用驼峰名法:首字母小写,其他的有意义的单词大写(尽可能语义化) add/insert/create/new (新增) rm (删除) sel/select/query/get (查询) info (信息) 1. 2. 3. 4. 不能使用关键字和保留字 JS中常用的数据类型 基本数据类型 数字nubmer (常规数字/NaN) 字符串 string (所有单引号、双引号、反引号抱...
DOCTYPE html>JavaScript debugging example//create a global variable for our vardisplay;functioninit() {//initialize only after the HTML has been loadeddisplay=document.getElementById("results"); }functionfirstParam() {//set breakpoint herevara=5; secondParam(a); }functionsecondParam(a) {varb=...
JavaScript是一种解释执行的脚本语言,是一种动态类型、弱类型、基于原型的语言,内置支持类型,它遵循ECMAScript标准。它的解释器被称为JavaScript引擎,为浏览器的一部分,广泛用于客户端的脚本语言,主要用来给HTML增加动态功能。 几乎所有主流的语言都可以编译为JavaScript,进而能够在所有平台上的浏览器中执行,这也体现了Java...
console.log (name); // Richard: the global variable 没有块级作用域: varname ="Richard"; // the blocks in this if statement do not create a local context for the name variable if(name) { name ="Jack";// this name is the global name variable and it is being changed to "Jack" h...
const carol = Object.create(personPrototype); JavaScript中的每个对象都有一个原型。原型是一个对象,其他对象可以从原型继承属性和方法。 类和继承 ES6引入了类的概念,使得基于原型的继承更加清晰和易于理解。类实际上是函数的另一种形式。 使用class关键字可以定义一个类。类可以包含构造器(constructor)和方法(...
Now, for convenience, let’s create a reference to thewhoAmImethod, presumably so we can access it merely bywhoAmI()rather than the longerobj.whoAmI(): varwhoAmI = obj.whoAmI; And just to be sure we’ve stored a reference to a function, let’s print out the value of our newwhoAmIva...
> this.foo // read global variable 'hello' > this.bar = 'world'; // create global variable > bar 'world' Note that the global object has prototypes. If you want to list all of its (own and inherited) properties, you need a function such asgetAllPropertyNames()fromListing All Proper...
函数外部声明的变量就是全局变量(global variable),它可以在函数内部读取。 varv =1;functionf() {console.log(v); } f()// 1 上面的代码表明,函数f内部可以读取全局变量v。 在函数内部定义的变量,外部无法读取,称为“局部变量”(local variable)。
Global variables defined with theletkeyword do not belong to the window object: Example letcarName ="Volvo"; // code here can not use window.carName Try it Yourself » Warning Do NOT create global variables unless you intend to. Your global variables (or functions) can overwrite window vari...
O_CREATE|O_RDWR);}elseif(what==6){close(fd);fd=open("/./grindir/./../b",O_CREATE|O_RDWR);}elseif(what==7){write(fd,buf,sizeof(buf));}elseif(what==8){read(fd,buf,sizeof(buf));}elseif(what==9){mkdir("grindir/../a");close(open("a/../a/./a",O_CREATE|O_...