1

        var a = 5 && true;
        var b = false || 6;
        var c = a + b;
        console.log(c);

等于7

       var a = 10;
        var b = a;
        typeof (a == b)

输入一个三位数字，计算这三个数字的乘积是多少

        var a = prompt("请输入一个数字");
        var baiwei = parseInt(a / 100);
        var shiwei = parseInt(a / 10) % 10;
        var gewei = a % 10;
        var product = Number(baiwei) * Number(shiwei) * Number(gewei);
        console.log(product);

        var a = null;
        var c = 10;
        var b = "我是字符串";
        var d = undefined;
        console.log(isNaN(a));
        console.log(isNaN(c));
        console.log(isNaN(b));
        console.log(isNaN(d));

image.png

       var a = "50px";
        var b = "px50";
        var c = "50px50";
        var d = 50.51;
       console.log(parseInt(a));
       console.log(parseInt(d));
       console.log(parseInt(c));
       console.log(parseInt(c));

image.png

2

小伙伴们，我们学习了parseFloat（）方法，下面我们将以下这几个数转化成浮点数：

“50px“，“px50“，“050px“，“50.12345“，“50.123px45“

并在页面中输出。

        var a = "50px";
        var b = "px50";
        var c = "050px";
        var d = 50.12345;
        var e="50.123px45";
       console.log(parseFloat(a));
       console.log(parseFloat(b));
       console.log(parseFloat(c));
       console.log(parseFloat(d));
       console.log(parseFloat(e));

image.png