The else statement is another conditional statement in JavaScript. Unlike if, it couldn't be specified alone — there has to be an if statement preceding an else. So what's else used for? The else statement executes a piece of code if the condition in the preceding if statement isn't me...
我是JavaScript的初学者,我试图在if/else语句中调用字符串数组。这就是我拥有的。它可以正常工作,但是执行此操作的方法较短。我不想使用任何其他方法。我只想坚持如果/else语句。 在这里输入代码 var welcomeMessage = prompt("what is your name?").toLowerCase(); var names = ["brad", "elena", "simon...
The above code also contains no conditions for the else statement. This means that the program will perform either the statement which is contained within the if statement or the code contained within the else statement. But you could add a condition to the else statement in which case the pr...
In JavaScript we have the following conditional statements: Useifto specify a block of code to be executed, if a specified condition is true Useelseto specify a block of code to be executed, if the same condition is false Useelse ifto specify a new condition to test, if the first condit...
In the above example, the outer if condition checks if a student has passed or failed using the condition marks >= 40. If it evaluates to false, the outer else statement will print Failed.On the other hand, if marks >= 40 evaluates to true, the program moves to the inner if...else...
// 1.双分支if(表达式1) { 代码块1; }else{ 代码块2; }// 2.多分支if(表达式1) { }elseif(表达式2) { } ...elseif(表达式2) { }else{ } if 嵌套 if(表达式1) {if(表达式2) { }... }... 2、switch语句 switch(表达式) {case值1: 代码块1;break;case值2: 代码块2;break;default:...
在脚本中使用if语句可以实现条件判断和控制流程。if语句的一般语法是: ``` if 条件: 执行语句块 elif 条件: 执行语句块 else: 执行语句块 ``` 条件...
是一种常见的编程技巧,可以根据特定条件对数据进行分类或转换。下面是一个完善且全面的答案: 在R中,使用if else条件可以根据指定的条件创建新变量。if else语句的一般格式如下: ```R ...
('flex-box-result').appendChild(h1).appendChild(h2); } }else{ var h1 = document.createElement('h1'); var textAnswer = document.createTextNode("Invalid Input. Please Try Again."); h1.setAttribute('id', 'ageInDays'); h1.appendChild(textAnswer); document.getElementById('flex-box-result...
if (2 in arr) { console.log("数组中存在元素2"); } else { console.log("数组中不存在元素2"); } ``` 输出结果为:"数组中存在元素2"。 2. 判断对象中是否存在某个属性 ```javascript let obj = {name: "Tom", age: 18, gender: "male"}; if ("age" in obj) { console.log("对象中...