<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Document</title>
</head>
<body>
<script>
//减少重复的代码把。
function getSum(a,b)
{
let res=a+b;
return res;
}
let num1 = 10;
let num2 = 20;
let result = getSum(num1, num2);
console.log(result);
</script>
</body>
</html>
