function isnumber(formu,msg){
       if(formu.value.length==0){
	      alert(msg);
	      formu.focus();
          return false;
        }
        RefString="1234567890.-";
        for (Count=0; Count < formu.value.length; Count++){
			TempChar= formu.value.substring (Count, Count+1);
			if (RefString.indexOf (TempChar, 0)==-1) {
				alert(msg);
				formu.focus();
				return false;
			}
        }
   return true;
}