var arrayMes=new Array("Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec")
 function countup(yr,m,d)
 {
  var today=new Date()
  var todayy=today.getYear()
   if (todayy < 1000)
    todayy+=1900
     var todaym=today.getMonth()
     var todayd=today.getDate()
     var todaystring=arrayMes[todaym]+" "+todayd+", "+todayy
     var paststring=arrayMes[m-1]+" "+d+", "+yr
     var difference=(Math.round((Date.parse(todaystring)-Date.parse(paststring))/(24*60*60*1000))*1)
    difference
    document.write("<b><font face='Arial' size='2' color='#EEEEEE'>"+difference+"&nbsp;&nbsp;</font></b>")
 }
 
 //cambiar la data
 countup(2003,05,15)