Question

Users would select their date from 3 dropdowns (day, month, year). I will combine them on server-side to make a string like ‘2008-12-30’. How can I then validate to make sure this date was in the right format/numeric only, etc?

Answer 1

If they are 3 separate drop-downs, you will need to validate them as three separate values.

Ie,

• Validate that the year column is numeric and between whatever years are valid in your app
• Validate that the month column is numeric
• Validate that the day column is numeric
• Validate that they are all valid values using checkdate()

Or, you could just cast them all to integer, combine them together into a date, and see if the resulting date is valid. Ie,

$time = mktime(0, 0, 0, (int)$_POST['month'], (int)$_POST['day'], (int)$_POST['year']);  // in this example, valid values are between jan 1 2000 (server time) and now // modify as required if ($time < mktime(0, 0, 0, 1, 1, 2000) || $time > time())   return 'Invalid!';  $mysqltime = date('Y-m-d', $time);  // now insert $mysqltime into database 

The downside to this method is that it’ll only work with dates within the Unix timestamp range ie 1970 to 2038 or so.