0096 data acquisition variable type typeof, literal

1. Obtain the data type of detection variable

typeof be used to obtain detected data type of the variable

var num = 18;
console.log(typeof num) // 结果 number      

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Different types of return value

        var num = 10;
        console.log(typeof num); // number
        var str = 'pink';
        console.log(typeof str); // string
        var flag = true;
        console.log(typeof flag); // boolean
        var vari = undefined;
        console.log(typeof vari); // undefined
        var timer = null;
        console.log(typeof timer); // object
        // prompt 取过来的值是 字符型的
        var age = prompt('请输入您的年龄');
        console.log(age);
        console.log(typeof age);

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2. literal

Literals in the source code is a fixed value represented by law, colloquially, showing how the expression is literal value.

• Digital literal: 8, 9, 10
• String literal: 'horse Programmers', "anterior end"
• Boolean literals: true, false