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 ...
JavaScript是一种脚本语言,可以嵌入到HTML中,通过<script>标签来引入。在JavaScript中,可以使用"if语句"来进行条件判断,根据条件的真假执行不同的代码块。以下是一个示例: 代码语言:txt 复制 <!DOCTYPE html> <html> <head> <title>Conditional Statement in HTML</title> </head> <body> <script> var ...
If you want to negate a if statement, we can do so using the NOT operator which reverses the Boolean value, and so changes it from true to false or from false to true.ReferencesLogical NOT (!) - JavaScript | MDN (mozilla.org) How to negate code in "if" statement block in ...
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 (...
HTML5学堂:在JavaScript中,我们可能很少会去用到 Label 语句,但是熟练的应用 Label 语句,尤其是在嵌套循环中熟练应用 break, continue 与 Label 可以精确的返回到你想要的程序的位置...一起走进这个比较陌生的命令吧。...Label 语句,按书本上说的语法是 Label: statement 如: begin: for (var i = 0; i <...
Use theifstatement to specify a block of JavaScript code to be executed if a condition is true. Syntax 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. ...
If it has value then display SUPPLYADDRESS and if doesn't have value then do not display SUPPLYADDRESS. I am using JAVASCRIPT. I am not able to find the correct syntax for IF statement. Can anyone solve my problem please. Thanks in advance.Know...
It is a lot easier to create an HTML element depending on a condition in Vue with thev-ifdirective than with plain JavaScript. With Vue you just write the if-statement directly in the HTML element you want to create conditionally. It's that simple. ...
The if StatementUse the if statement to specify a block of JavaScript code to be executed if a condition is true.Syntaxif (condition) { block of code to be executed if the condition is true } Note that if is in lowercase letters. Uppercase letters (If or IF) will generate a ...
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 // ...