//随机颜色;
    function randColor() {
        return '#' +
                (function (color) {
                    return (color += '0123456789abcdef'[Math.floor(Math.random() * 16)])
                    && (color.length == 6) ? color : arguments.callee(color);
                })('')
    }

    //console.log(randColor());
    //$("#menu").attr("style", "background-color:" + randColor());

//获取随机颜色数组
    function getColor(num) {
        var colorList = [];
        for (var i = 0; i < num; i++) {
            colorList.push(randColor());
        }
        return colorList;
    }

    console.log(getColor(5));

<div id="menu"></div>

//获取随机颜色数组
    function getColor(num) {
        for (var i = 0; i < num; i++) {
            var html = "<div style='height: 30px;line-height:30px;color:#000;text-align:center;background-color:" + randColor() + "'>" + randColor() + "</div>";
            $("#menu").append(html);
        }
    }

    getColor(20);