function zeropad (str,num)
{
    var newstr = '';

    str = "00000000" + str;

    var size = str.length;
    
    newstr = str.substr( (size-num), num );

    return newstr;
}

function make_datestr(element, target) 
{
  var theform = element.form;

  eval("sec = zeropad(theform."+target+"sec.value,2);");
  eval("min = zeropad(theform."+target+"min.value,2);");
  eval("hour = zeropad(theform."+target+"hour.value,2);");
  eval("day = zeropad(theform."+target+"day.value,2);");
  eval("month = zeropad(theform."+target+"month.options[theform."+target+"month.selectedIndex].value,2);");
  eval("year = zeropad(theform."+target+"year.value,4);");

  datestr = year + "-" + month + "-" + day + " " + hour + ":" +  min + ":" + sec;

  eval("theform."+target+".value = datestr;");
}