PHP date function accept null or empty string and return value

Question

it's amzing when i send a null value in date() as a second parameter then it returns some time? how to remove this thing. i want that if a string is null or empty then doesn't do anything

    $x=strtotime();
    var_dump($x);
    var_dump($x==NULL);
    echo date('H:i',$x);

display

 Warning: strtotime() expects at least 1 parameter, 0 given in 
 D:\xampp\htdocs\test\index.php on line 1
 bool(false) bool(true) 05:30

Answer 1

Why not check the value of $x?

if($x != NULL)
    echo date('H:i',$x);

Answer 2

The second parameter to the date() function is optional: if it's not provided, date() uses the current time. If you want to prevent this you have to check your variable before calling it, or write a wrapper function and use that instead of date().

Answer 3

It makes perfect sense. NULL equals 0 in this case. date() counts from 0, which was January 1st, 1970, 0:00:00 UTC.

You are based in Jaipur. Your timezone is UTC + 5:30 hours. Thus, date(0) on your server, in your time zone, will result in January 1st, 1970, 5:30.