function grafico(str) { 

larg=675; 
alt=449;
toptop=(screen.height/2)-(alt/1.8); 
leftleft=(screen.width/2)-(larg/2); 

searchWin = window.open(str,'','top='+toptop+',left='+leftleft+',scrollbars=no,width='+larg+',height='+alt+',status=no,location=no,toolbar=no'); 


}