if( condition ) {//statement}else{//statement (whencondition evaluates tofalse)} 以下流程图说明了 if else 语句。 请参阅以下示例: letx =5;if(x >10) {console.log('x is greater than 10');}else{console.log('x ...
// 使用 if/elseletresult;if(condition){result='value1';}else{result='value2';}// 使用三元运算符constresult=condition?'value1':'value2'; 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 甚至可以链式使用,替代简单的 if/else if/else 结构: 复制 constdiscount=user.type==='premium'?0.2:user.ty...
使用if/else语句是一种在JavaScript中实现条件判断的常见方法。if/else语句允许根据条件的真假执行不同的代码块。 概念: if/else语句是一种控制流语句,用于根据条件的真假执行不同的代码块。它基于一个条件表达式,如果条件为真,则执行if代码块;如果条件为假,则执行else代码块。 分类: if/else语句是条件语句的一种...
const conditionDict = { condition1: function() { // 处理代码块1 }, condition2: function() { // 处理代码块2 }, condition3: function() { // 处理代码块3 } }; if (condition in conditionDict) { conditionDict[condition](); } else { // 默认处理代码块 } 使用数组和函数:可以使用一个...
if(condition) { //block of code to be executed if the condition is true } Note thatifis in lowercase letters. Uppercase letters (If or IF) will generate a JavaScript error. Example Make a "Good day" greeting if the hour is less than 18:00: ...
if...else if...else 语句- 使用该语句来选择多个代码块之一来执行 switch 语句- 使用该语句来选择多个代码块之一来执行 1.1 if语句 只有当指定条件为 true 时,该语句才会执行代码。 if(condition) { 当条件为 true 时执行的代码 } 1. 2. 3. 1.2...
· if...else if...else 语句- 使用该语句来选择多个代码块之一来执行 · switch 语句 - 使用该语句来选择多个代码块之一来执行 1.1 if语句 只有当指定条件为 true 时,该语句才会执行代码。 if(condition) { 当条件为 true 时执行的代码 } 1.2 if...else语句 使用 if...else 语句在条件为 true 时执...
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...
Using NOT in the if statement JavaScript also has another logical operator which can be used in the if statement. So far we have tested a condition to see if it is true. But JavaScript has a really simple way of toggling between true and false. By adding an ! to any condition you cha...
execute if condition2 is true } else { execute if neither condition1 nor condition2 is true } Example Program A renowned club in the town want to create a program to vet the age of the people applying for membership. They want to only allow people older than 18. For senior citizens, ...