if conditional judgment statement in JavaScript

if conditional judgment statement:

#If the condition is true, what code will be executed; if the condition is not true, what code will be executed

Structure 1: Only judge true (true), if the condition is false, do nothing

if (Conditional judgment: the judgment result is a Boolean value)

{

The condition is true (true), the executed code

}

## Structure 2: Both true and false

if (Conditional judgment)

{

If the condition is true, the code to be executed

}else

{

The condition is false, the code to be executed Code

}

# Structure 3: Multi-condition judgment
if(Condition 1)

{

Code 1;

}else if(Condition 2)

{

Code 2;

}else if(condition 3)

{

Code 3;

}else

{

If none of the above conditions are true, execute this code;

}

Note: Although there are multiple conditions, there is an "OR" relationship between the conditions. . At any moment, only one condition can be true, and multiple conditions cannot be met at the same time.

<!DOCTYPE HTML>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=utf-8">
        <title>php.cn</title>
        <script>
        //给一个成绩
        var score=89;
        //判断成绩所属级别
        if(score<60){
            document.write("对不起，没有及格");
        }else if (score>=60&&score<70){
            document.write("刚好及格");
        }else if(score>=70&&score<80){
            document.write("成绩良好");
        }else if(score>=80&&score<90){
            document.write("成绩优秀");
        }else if(score>=90&&score<100){
            document.write("试卷这么难，这样的成绩简直逆天");
        }else{
            document.write("对不起，你的成绩超出系统判断范围，请重新输入");
        }
        
        </script>
    </head>
    <body>
    </body>
</html>

Continuing Learning

new file

<!DOCTYPE HTML> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>php.cn</title> <script> //给一个成绩 var score=89; //判断成绩所属级别 if(score<60){ document.write("对不起，没有及格"); }else if (score>=60&&score<70){ document.write("刚好及格"); }else if(score>=70&&score<80){ document.write("成绩良好"); }else if(score>=80&&score<90){ document.write("成绩优秀"); }else if(score>=90&&score<100){ document.write("试卷这么难，这样的成绩简直逆天"); }else{ document.write("对不起，你的成绩超出系统判断范围，请重新输入"); } </script> </head> <body> </body> </html>

submit Reset Code

Automatic operation

if conditional judgment statement in JavaScript

ElementaryImperial CMS enterprise imitation website tutorial

ElementaryNewbies with zero foundation in WordPress build personal blogs and corporate websites

ElementaryUltimate CMS zero-based website building instruction video

ElementaryFront-end project-Shangyou [HTML/CSS/JS technology comprehensive practice]

IntermediateVue3.0 from 0 to build a universal backend management system project practice

ElementaryZero-based front-end course [Vue advanced learning and practical application]

ElementaryWEB front-end tutorial [HTML5+CSS3+JS]

ElementaryQuick introduction to apipost

IntermediateVue3+TypeScript practical tutorial-enterprise-level project practice

ElementaryLet's briefly talk about starting a business in PHP

IntermediateVUE e-commerce project (front-end & back-end dual project actual combat)

ElementaryApipost practical application [api, interface, automated testing, mock]