function addRollover(img,roller){

    if(typeof img == "string"){

        var id = img;

        img = null;

        

        if(document.getElementById){

            img = document.getElementById("id");

        } else if(document.all){

            img = document.all["id"];

        }

        

        if(!img)img = document.images[id];

        if(!img)return

    }

    

    if(img.tagName.toLowerCase()!="img")return;

    

    var base = img.src;

    (new Image()).src = roller;



    img.onmouseover = function(){img.src = roller;}

    img.onmouseout  = function(){img.src = base;}

}



function initRollover(){

    var images = document.getElementsByTagName("img");

    for(var i=0;i<images.length;i++){

        var image = images[i];

        var roller = image.getAttribute("roller");

        if(roller){

            addRollover(image,roller);

        }

    }

}