log(i); //output = numbers between 0 and 9 } console.log(i) //returns 10 Listing 3-4A var Statement Will Retain Its Value After the Code Block Has Been Executed 如果var的行为类似于let,您将得到相同的结果,其中i的值将返回undefined。相反,循环的行为完全相同,但是在这种情况下,您的变量是可以...
We can omit { } in if…else statements when we have a single line of code to execute. For example, let num = 4; // if condition if (num % 2 == 0) console.log("even number"); else console.log("odd number"); // Output: even number Run Code JavaScript...
// Two slashes start single-line commentsvarx;// 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 conditional statementif(x===0){// Is ...
functionquote(str,config){const{char='"',skipIfQuoted=true}=config;constlength=str.length;if(skipIfQuoted&&str[0]===char&&str[length-1]===char){returnstr;}returnchar+str+char;}quote('Hello World',{char:'*'});// => '*Hello World*'quote('"Welcome"', { skipIfQuoted: true }); ...
// A conditional statement if (x === 0) { // Is `x` equal to zero? x = 123; } // 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。
JavaScript includes three forms of if condition: if condition, if else condition and else if condition. The if condition must have conditional expression in brackets () followed by single statement or code block wrapped with . 'else if' statement must be placed after if condition. It can be ...
QuickJS 是在 MIT 许可下发的一个轻量 js 引擎包含 js 的编译器和解释器,支持最新 TC39 的 ECMA-262 标准。QuickJS 和其它 js 引擎的性能对比,可以参看 QuickJS 的 benchmark 对比结果页,从结果看,JerryScript 内存和体积小于 QuickJS,但各项性能均低于 QuickJS,Hermes 体积和内存大于 QuickJS,性能和 QuickJS 差...
Multi-line Statements Lines MUST not be longer than 80 characters When a statement is too long to fit on a line, line breaks MUST occur after an operator Semicolons Semicolons MUST NOT be used to terminate statements except the next line starts with an(,[or` ...
The function is invoked with a single argument multiply(5). Initially a parameter is 2 and b is undefined. The conditional statement verifies whether b is undefined. If it happens, b = 2 assignment sets a default value. 尽管提供了分配默认值的方...
IfStmt: an if statement; use IfStmt.getCondition(), IfStmt.getThen() and IfStmt.getElse() to access its condition expression, “then” branch and “else” branch, respectively. LoopStmt: a loop; use Loop.getBody() and Loop.getTest() to access its body and its test expression, respectiv...