20-类型判断.html

<!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>
    <script>
        // typeof 检测数据类型
        
        let age = 18
        let ageT = typeof age
        document.write(ageT == "number", "<br>")

        let name = "wxy"
        let nameT = typeof name
        document.write(nameT == "string", "<br>")

        let gender = false
        let genderT = typeof gender
        document.write(genderT == "boolean", "<br>")

        let empty = null
        let emptyT = typeof empty
        document.write(emptyT == "object")
    </script>
</body>
</html>