var ns4 = (document.layers)? true:false 
            var ie4 = (document.all)? true:false 
            var ns6 = (document.getElementById && !document.all) ? true: false; 
            var coorX, coorY; 

            if (ns6) document.addEventListener("mousemove", mouseMove, true) 
            if (ns4) {document.captureEvents(Event.MOUSEMOVE); document.mousemove = mouseMove;} 

            function mouseMove(e)    { 
                if (ns4||ns6)    { 
                    coorX = e.pageX; 
                    coorY = e.pageY; 
                } 
                if (ie4)    { 
                    coorX = event.x; 
                    coorY = event.y; 
                	coorX += document.documentElement.scrollLeft; 
                	coorY += document.documentElement.scrollTop; 
                } 
                return true; 
            } 

            function ini()    { 
                if (ie4)    document.body.onmousemove = mouseMove; 
            } 

            function mostrar(dato)    { 
                with(document.getElementById("preview"))    { 
                    style.top = coorY + 15 +'px'; 
                    style.left = coorX - 140 +'px'; 
                    style.visibility = "visible"; 
                    innerHTML = dato; 
                } 
            } 

            function ocultar()    { 
                document.getElementById("preview").style.visibility = "hidden"; 
            } 

            function mover()    { 
                with(document.getElementById("preview"))    { 
                    style.top = coorY + 15 +'px'; 
                    style.left = coorX - 140 +'px';
                } 
            } 


function screenshot(img, ancho, alto){
  derecha=(screen.width-ancho)/2;
  arriba=(screen.height-alto)/2;
  string="toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=1,width="+ancho+",height="+alto+",left="+derecha+",top="+arriba+"";
  fin=window.open(img,"",string);
}