debugger, default, delete, do, else, finally, for, function, if, in, instanceof, new, return...
if,else,for,in,continue,break,do,while,switch,case,default,return, try,catch,throw, var,void, new,delete this, typeof, function, with, instanceof, finally, debugger 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 保留字 int,short,boolean,long,double,char,float private,public,protected, a...
利用这个特性,可以通过&&和||运算符来缩短if...else语句。例如: let x = 10; let result; if (x > 5) { result = "x is greater than 5"; } else { result = "x is less than or equal to 5"; } // 利用 && 运算符 let x = 10; let result = x > 5 && "x is greater than 5"...
// condition 1: check if animal has a value if(animal) { // condition 2: check if animal has a type property if(animal.type) { // condition 3: check if animal has a name property if(animal.name) { // condition 4: check if animal has a gender property if(animal.gender) { resu...
短路求值 是使用 三元运算、&& 和 || 快速求值的方法。使用短路求值,在一行代码内表达出简单的条件赋值 (if...else if...else 或 switch...c...
javascript关键字有:break、else、new、var、case、finally、return、void、catch、for、switch、while、continue、function、this、with、default、if、throw、delete、in、try、do、instranceof、typeof等。 Javascript关键字(Reserved Words)是指在Javascript语言中有特定含义,成为Javascript语法中一部分的那些字。Javascript...
Short-circuit Evaluation 如果参数是null或者是undefined,我们可以简单的使用一个Short-circuit逻辑运算,实现一行代码替代六行代码的写法。 Longhand: letdbHost; if(process.env.DB_HOST) { dbHost= process.env.DB_HOST; } else{ dbHost= 'localhost';} ...
vara=10;if(a>5){console.log("a > 5");}elseif(a<5){console.log("a < 5");}else{console.log("a = 5");} 8.3 switch 代码语言:javascript 复制 varday=newDate().getDay();switch(day){case0:console.log("Sunday");break;case1:console.log("Monday");break;default:console.log(".....
Short-circuit Evaluation 如果参数是null或者是undefined,我们可以简单的使用一个Short-circuit逻辑运算,实现一行代码替代六行代码的写法。 Longhand: let dbHost;if (process.env.DB_HOST) { dbHost = process.env.DB_HOST; } else { dbHost = 'localhost'; } ...
if (tz < 0) s += tz / 60 + " hours before GMT"; else if (tz == 0) s += "GMT"; else s += tz / 60 + " hours after GMT"; return(s); } (9)getYear函数:返回日期的"年"部分。返回值以1900年为基数,例如1999年为99。前面有例子。