JavaScript switch statement
The switch statement is used to perform different actions based on different conditions.
JavaScript switch statement
Use the switch statement to select one of multiple blocks of code to execute.
Syntax
switch(n)
{
case 1:
Execute code block 1
break;
case 2:
Execute code block 2
break;
default:
n Code that is not executed simultaneously with case 1 and case 2
}
{
case 1:
Execute code block 1
break;
case 2:
Execute code block 2
break;
default:
n Code that is not executed simultaneously with case 1 and case 2
}
Working principle: First set the expressionn (usually a variable). The value of the expression is then compared with the value of each case in the structure. If there is a match, the code block associated with the case is executed. Please use break to prevent the code from automatically running to the next case.
Instance
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p>点击下面的按钮来显示今天是周几：</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
function myFunction(){
var x;
var d=new Date().getDay();
switch (d){
case 0:x="今天是星期日";
break;
case 1:x="今天是星期一";
break;
case 2:x="今天是星期二";
break;
case 3:x="今天是星期三";
break;
case 4:x="今天是星期四";
break;
case 5:x="今天是星期五";
break;
case 6:x="今天是星期六";
break;
}
document.getElementById("demo").innerHTML=x;
}
</script>
</body>
</html>Run Instance»
Click the "Run Instance" button to view the online instance
default keyword
Please use the default keyword to specify what to do when the match does not exist:
Example
<html>
<head>
<meta charset="utf-8">
<title>php中文网(php.cn)</title>
</head>
<body>
<p>点击下面的按钮，会显示出基于今日日期的消息：</p>
<button onclick="myFunction()">点击这里</button>
<p id="demo"></p>
<script>
function myFunction()
{
var x;
var d=new Date().getDay();
switch (d)
{
case 6:x="今天是星期六";
break;
case 0:x="今天是星期日";
break;
default:
x="期待周末";
}
document.getElementById("demo").innerHTML=x;
}
</script>
</body>
</html>Run Instance»
Click the "Run Instance" button to view the online instance
