其他数据类型转布尔类型

Posted 2020-10-27 澎湃_L

★数字和字符串转完之后为true。

★undefined、null、0转完之后为false.

        var n1=123;
        var n2="345"
        var n3;
        var n4=null;
        var n5=Infinity;
        var n1=Boolean(n1);
        var n2=Boolean(n2);
        var n3=Boolean(n3);
        var n4=Boolean(n4);
        var n5=Boolean(n5);
        document.write("n1的值是:" + n1+ "<br>" + "n1的类型是:"+typeof(n1) + "<br>");
         document.write("n2的值是:" + n2+ "<br>" + "n2的类型是:"+typeof(n2) + "<br>");
         document.write("n3的值是:" + n3+ "<br>" + "n3的类型是:"+typeof(n3) + "<br>");
         document.write("n4的值是:" + n4+ "<br>" + "n4的类型是:"+typeof(n4) + "<br>");
        document.write("n5的值是:" + n5+ "<br>" + "n5的类型是:"+typeof(n5) + "<br>");
        /*页面输出结果为：
        n1的值是:true
        n1的类型是:boolean
        n2的值是:true
        n2的类型是:boolean
        n3的值是:false
        n3的类型是:boolean
        n4的值是:false
        n4的类型是:boolean
        n5的值是:true
        n5的类型是:boolean*/