var num = Math.random()*;

        var num1 = Math.floor(num); // 向下取整

        var num2 = Math.ceil(num); // 向上取整

        document.write(num2+'-<br>');

        document.write(num1);

        // 1-10 随机数

        var a = Math.floor(Math.random()*+);

        console.log(a);

        function selectForm(min,max){

            var ta = max - min + ;

            return Math.floor(Math.random() * ta + min);

        }

        console.log(selectForm(,));

        var colors = ["red","gree","blue","yellow","black"];

        var color = colors[selectForm(,colors.length-)];

        console.log(color);