function setRandom(imageId){

            // random image function, by Simon Watt simon@ingenuity.co.nz

            var ImagePath;   

            var imageArray = new Array("images/mainimg01.jpg","images/mainimg02.jpg","images/mainimg03.jpg","images/mainimg04.jpg","images/mainimg05.jpg","images/mainimg06.jpg","images/mainimg07.jpg","images/mainimg08.jpg","images/mainimg09.jpg");


            var ranNo = Math.floor(Math.random() * (imageArray.length ));    

            var imagePath = imageArray[ranNo];

            document.getElementById(imageId).src = imagePath;       

}