How to validate a date from user input?

Question

I want to validate the birthdate from user input. I'm using HTML 5 and Internet Explorer 8. I want to ensure that the date is in mm/dd/yyyy format and not more than the present date.

Answer 1

Is there a requirement to use IE8? It does not have great support for HTML5. Chrome, Firefox or Microsoft Edge are what you should be using.
That said.
<input type="text" name="date" placeholder="mm/dd/yyyy" pattern="(0?[1-9]|1[012])/(0?[1-9]|[12][0-9]|3[01])/\d{4}" required />
The html5 will do the pattern matching on the input and get you mm/dd/yyyy
when you submit the form to php have the following:
$todayTime = mktime(0, 0, 0, date('m'), date('d'), date('Y'));
$formTime = strtotime($_POST['date']);
if ($formTime > $todayTime) {
// error because submitted date greater than today
}

Answer 2

$arr = explode(”/”, $date);
if(checkdate($arr[0], $arr[1], $arr[2])) {
/*True*/
}

Answer 3

split month, date and day to array and use checkdate function

Answer 4

yeah, thanks guys I already figure it out... but thanks for the suggestions and advices....
For now I just only have IE8 and no chrome installed in my Uncle's laptop.