<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>Document</title>
</head>
<body>
<h2 id ="res"> </h2>
<script>
//把十赋给a
var a =10;
a+=10;//<===>a=a+10
a-=10;//<===>a=a-10
a*=10;//<===>a=a*10
a/=10;//<===>a=a/10
a%=10;//<===>a=a%10
document.getElementById ("res").innerHTML= a ;
</script>
</body>
</html>
