error cheking for date input

greedyisg00d

Hi I am just new to programing and I am working on an scheduler for meetings. I have 2 textbox by default

textbox1 -> $date_from
textbox2->$date_to

My problem is I want to have an error checking or invalid input checker when the user clicks the submit button. For example when the user enter a previous date which must be invalid and the value of the $date_from is ahead of $date_to.

Example:
$date_from -> 02-Feb-2001
$date_to -> 14-Feb-2001 //must be invalid because its a previous date

$date_from -> 1-Mar-2009
$date_to -> 18-Feb-2009 //must be invalid because $date_from is ahead of $date_to

Any idea on how can I create error checking and display the error?

Thanks

Installer

Don't use text input to get dates; too many problems can result. Use select options instead to simplify matters. And since the dates are bound for a database, use "Y-m-d" format.

bradgrafelman

As Installer suggests, using three select boxes (one each for year, month, and day) is the best way to ensure that you get a valid date format (one that is easy for you to work with) for working with a database (you are working with a DB, right?).

That way, you could construct and check the dates like so:

$date_from = "$_POST[from_year]-$_POST[from_month]-$_POST[from_day]";
$date_to = "$_POST[to_year]-$_POST[to_month]-$_POST[to_day]";

if(strtotime($date_from) > strtotime($date_to)) {
    // invalid
} else {
    // insert dates into DB (after sanitizing e.g. with mysql_real_escape_string())
}

greedyisg00d

Actually I have a javascript calendar and the dates that are selected are inputed into a textbox. Btw can you give me a sample code of what you meant so that I can analyze it on how it works. Thanks

bradgrafelman

The Javascript calendar would be another alternative. Either way, you want to get your dates in the standard "YYYY-MM-DD" format so that they are easier to work with.

Installer

This would generate some select elements:

echo '<select name="from_month">';
$cal_info = cal_info(1);
foreach ($cal_info['months'] as $key => $month) {
    echo '<option value="' . str_pad($key, 2, '0', STR_PAD_LEFT) . '">' . $month . '</option>';
}
echo '</select>';

echo '<select name="from_day">';
for ($day = 0; $day <= 31; $day++) {
    echo '<option value="' . str_pad($day, 2, '0', STR_PAD_LEFT) . '">' . $day . '</option>';
}
echo '</select>';

echo '<select name="from_year">';
for ($year = date('Y'); $year > 1969; $year--) {
	  echo '<option value="' . $year . '">' . $year . '</option>';
}
echo '</select>';

greedyisg00d

Thanks a lot. how about if the dates that are inputted are previous dates for example feb-14-1992 which is invalid. Since the scheduler must set dates from current to future dates only.

Installer

Brad's first post shows you how to construct and compare the date strings. Just adapt that.