// convert decimal value (0 - 255) to hexadecimal

// (use .toString(16) method supported by IE)

function toHex(dec) {

        // create list of hex characters

        var hexCharacters = "0123456789ABCDEF"

        // if number is out of range return limit

        if (dec < 0)

                return "00"

        if (dec > 255)

                return "FF"

        // decimal equivalent of first hex character in converted number

        var i = Math.floor(dec / 16)

        // decimal equivalent of second hex character in converted number

        var j = dec % 16

        // return hexadecimal equivalent

        return hexCharacters.charAt(i) + hexCharacters.charAt(j)

}

// set background color to specified descriptors

function setbgColor(red, green, blue) {

         document.bgColor = "#" + toHex(red) + toHex(green) +

toHex(blue)

}

// fade from start to end descriptors (increase step to increase transition speed)

function fade(sred, sgreen, sblue, ered, egreen, eblue, step) {

        // loop to create fade effect

        for(var i = 0; i <= step; ++i) {

                // set current red descriptor

                var red = Math.floor(sred * ((step - i) / step) + ered

* (i / step))

                // set current green descriptor

                var green = Math.floor(sgreen * ((step - i) / step) +

egreen * (i / step))

               // set current green descriptor

                var blue = Math.floor(sblue * ((step - i) / step) +

eblue * (i / step))

                // set background color according to descriptors

                setbgColor(red, green, blue)

        }

}