function number( field, type )
{
   var value;
   var new_value;
   var index;
   var digits;
   
   if ( type == 0 ) // Number
      digits = "0123456789";
   else if ( type == 1 ) // Decimal
      digits = "0123456789-";
   else if ( type == 2 ) // Date
      digits = "0123456789/";
   
   value = field.value;
   new_value = '';
   
   keycode = window.event.keyCode;
   
   if ( keycode != 8  && 
        keycode != 37 && 
        keycode != 39 && 
        keycode != 38 && 
        keycode != 40 && 
        keycode != 13 ) {
      for( i=0; i < field.value.length; i++ )
      {
         index = value.substr(i,1);
      
         if ( ("0123456789").indexOf( index ) > -1 )
            new_value += index;
      }
   
      field.value = new_value;
   }
}