Date format validation in PHP

Validate the date which is entered from textbox in “YYYY-MM-DD” format. Well, we can validate the format of the date using regular expression but how to validate weather that date is valid date or not, such as “2007-02-29″ is the correct format of the date but it’s not the valid date.
To overcome that situation, I’ve used checkdate() function available in PHP for validation of date.

Function to validate date format in PHP
function checkDateFormat($date)
{
//match the format of the date
if (preg_match ("/^([0-9]{4})-([0-9]{2})-([0-9]{2})$/”, $date, $parts))
{
//check weather the date is valid of not
if(checkdate($parts[2],$parts[3],$parts[1]))
return true;
else
return false;
}
else
return false;
}

In the above function, first of all format of date is validated using regular expression. As you can see the in the preg_match() function, there are three expression each separated by “-” and there can be only digits of length of 4,2 and 2 in these expressions. If the date format is incorrect then this function returns “false” value. And, if the supplied string contains the valid date format then the part matching each expression are stored in the “$parts” array. Such as, if we supply “2007-03-12″ then “2007″, “03″ and “12″ are stored in the “$parts” array. After that, checkdate() function of PHP is used check weather the supplied date is valid date or not.

Example

echo checkDateFormat("2008-02-29"); //return true
echo checkDateFormat("2007-02-29"); //return false