// # of images
            var imgCount = 30;
            // image directory
            var dir = '';
            // random the images
            var randomCount = Math.round(Math.random() * (imgCount - 1)) + 1;
            // array of images & file name
            var images = new Array
                    images[1] = "_BGIMG01.jpg",
        images[2] = "_BGIMG02.jpg",
        images[3] = "_BGIMG03.jpg",
        images[4] = "_BGIMG04.jpg",
        images[5] = "_BGIMG05.jpg",
        images[6] = "_BGIMG06.jpg",
        images[7] = "_BGIMG07.jpg",
        images[8] = "_BGIMG08.jpg",
        images[9] = "_BGIMG09.png",
        images[10] = "_BGIMG10.jpg",
        images[11] = "_BGIMG11.jpg",
        images[12] = "_BGIMG12.jpg",
        images[13] = "_BGIMG13.jpg",
        images[14] = "_BGIMG14.jpg",
        images[15] = "_BGIMG15.jpg",
        images[16] = "_BGIMG16.jpg",
        images[17] = "_BGIMG17.jpg",
        images[18] = "_BGIMG18.jpg",
        images[19] = "_BGIMG19.jpg",
        images[20] = "_BGIMG20.jpg",
        images[21] = "_BGIMG21.jpg",
        images[22] = "_BGIMG22.jpg",
        images[23] = "_BGIMG23.jpg",
        images[24] = "_BGIMG24.jpg",
        images[25] = "_BGIMG25.jpg",
        images[26] = "_BGIMG26.jpg",
        images[27] = "_BGIMG27.jpg",
        images[28] = "_BGIMG28.jpg",
        images[29] = "_BGIMG29.jpg",
        images[30] = "_BGIMG30.jpg",


            document.body.style.backgroundImage = "url(" + dir + images[randomCount] + ")";