在 JavaScript 中的算術運算符如下
- +
- -
- *
- /
- %
算術運算符的優先級和結合性
* / % 的優先級要高于 + -，無論是 + - * / %都是左結合性(從左至右計算)
加
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
let resultOne = 1 + 1;
console.log(resultOne);
let num1, num2;
num1 = 3;
num2 = 5;
let resultTwo = num1 + num2;
console.log(resultTwo);
let resultThree = num1 + 3;
console.log(resultThree);
</script>
</head>
<body>
</body>
</html> 
減
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
let resultOne = 2 - 1;
console.log(resultOne);
let numOne, numTwo;
numOne = 3;
numTwo = 9;
let resultTwo = numOne - numTwo;
console.log(resultTwo);
</script>
</head>
<body>
</body>
</html> 
乘
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
let result = 1 + 2 * 5;
console.log(result);
</script>
</head>
<body>
</body>
</html> 除
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
let result = 1 / 3;
console.log(result);
</script>
</head>
<body>
</body>
</html> 取餘
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Demo</title>
<script>
/*
被除數 除數 商 餘數
10 ÷ 3 = 3 1
*/
let result = 10 % 3;
console.log(result);
</script>
</head>
<body>
</body>
</html>