function showpic(naam) {
x=1;
y=1;
width=300;
height=350;
if(window.screen){
 per_ancho=(width/800)*100;
 per_alto=(height/width)*100;
 win_ancho=(screen.width*per_ancho)/100;
 win_alto=(win_ancho*per_alto)/100;
 x=(screen.width-win_ancho)/2;
 y=(screen.height-win_alto)/2;
 y=y-40;
 if (y<0) {
  y=0;
  }
 }
s="showpic.html?pic="+naam;
w=window.open(s,"picshow","width=300,height=350,left="+x+",top="+y+",resizable=0,status=0,toolbar=0,scrollbars=0");
if (window.screen) {
 w.focus();
 }
}