if( condition )statement_1statement_2; 如果不使用花括号,将很难看出 statement_2 不属于 if 块。 如果您想在条件计算结果为 false 时执行另一条语句,请按如下方式使用 else: if( condition ) {//statement}else{//statement (...
如果您想在条件计算结果为 false 时执行另一条语句,请按如下方式使用 else: if( condition ) { // statement } else { // statement (when condition evaluates to false) } 1. 2. 3. 4. 5. 以下流程图说明了 if else 语句。 请参阅以下示例: let x = 5; if (x > 10) { console.log...
Useelse ifto specify a new condition to test, if the first condition is false Useswitchto specify many alternative blocks of code to be executed Theswitchstatement is described in the next chapter. The if Statement Use theifstatement to specify a block of JavaScript code to be executed if ...
if (condition) statement1 else statement2 1. 其中condition可以是任何表达式,计算的结果甚至不必是真正的 boolean 值,ECMAScript 会把它转换成 boolean 值。 如果条件计算结果为 true,则执行statement1;如果条件计算结果为 false,则执行statement2。 每个语句都可以是单行代码,也可以是代码块。 还可以串联多个 if ...
The else StatementUse the else statement to specify a block of code to be executed if the condition is false.if (condition) { block of code to be executed if the condition is true } else { block of code to be executed if the condition is false }...
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 If 语句 只有当指定条件为 true 时,该语句才会执行代码。 语法 if (条件) { 只有当条件为 true 时执行的代码 } 注意:请使用小写的 if。使用大写字母(IF)会生成 JavaScript 错误! 实例...
This is the typical logic that guides conditional logic, and basically the if/else statement. However, we can always expand the way we work around the if/else statement with other Boolean operators such as not, and, etc.To negate code in JavaScript, we can make use of the JavaScript ...
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...
JavaScript else StatementWe use the else keyword to execute code when the condition specified in the preceding if statement evaluates to false.The syntax of the else statement is:if (condition) { // block of code // execute this if condition is true } else { // block of code // ...
To write this set of code we need to write a compound if else statement using Boolean logic to test if both conditions are true. How to use AND, OR in the JavaScript IF statement As mentioned above, the condition for the if statement need not be a single variable but can consist of ...