b1 = new Image(); b1.src = "images/pagpr.jpg";
    b1p= new Image(); b1p.src = "images/pagpr-P.jpg";
    b2 = new Image(); b2.src = "images/m_site.jpg";
    b2p= new Image(); b2p.src = "images/m_site-P.jpg";
    b3 = new Image(); b3.src = "images/contac.jpg";
    b3p= new Image(); b3p.src = "images/contac-P.jpg";



    function cambiaimg(imgid,imgnew)
    {
        if(navigator.appVersion.substring(0,1)>=3)
            document.images[imgid].src=eval(imgnew+".src");
    }