php drop down detect selection

Question

I have a date of birth, and when the user is over Feb (02), the days should go only to 29. As you can see I'm using $month="1" just to test it. I'm supposed to use PHP only, no JavaScript or anything else. How would i go about making that?

<?php
$month="1"; // <-- currently using this to make it 29,30 or 31 days

print "<select name='day'>";
if  ($month==1){
    for ($i=0; $i<=28; $i++)    
    {
        $day = 1 + $i;
        print "<option value = $day>" . $day ."</option>";
    }
}
if  ($month==2){
    for ($i=0; $i<=29; $i++)
    {
        $day = 1 + $i;
        print "<option value = $day>" . $day ."</option>";
    }
}


print "</select>";

print "<select name='month'>";
for ($i=0; $i<=11; $i++)
{

    $month = 1 + $i;
    print "<option value = $month>" .$month ."</option>";
}
print "</select>";

?>

$month == 1 not $month =="1". Otherwise it is an string. — Sablefoste
– Sablefoste, Commented Aug 6, 2012 at 16:16
@Sable PHP evaluates $month == 1 and $month == "1" to be the same. $month === 1 and $month === "1" are different. — Matt
– Matt, Commented Aug 6, 2012 at 16:22
It's actually the same thing with a loose comparison. This would also be true: $month == "1 foo bar". If he had used the strict comparison ($month === x) however, it would be a different story. — F. Orvalho
– F. Orvalho, Commented Aug 6, 2012 at 16:23
@bob12345 you might want to use a switch statement instead of all those if statements. It won't change the functionality, but it will clean up your code a bit. — Matt
– Matt, Commented Aug 6, 2012 at 16:23
or create an array with key $month and value of number of days in that month and use just 1 piece of code like print "<select name='day'>"; for ($day=1; $day<=$n_days[$month]; $day++) print "<option value='$day'>$day</option>"; print "</select>"; — F. Orvalho
– F. Orvalho, Commented Aug 6, 2012 at 16:28

Niet the Dark Absol · Accepted Answer · 2012-08-06 16:15:48Z

3

Once PHP sends stuff to the browser, it is done. It cannot affect the page in any way.

JavaScript, on the other hand, takes over when the browser gets the page. It CAN change the page, and it can even ask the server to do something (in which case PHP may get involved).

In other words, you cannot do what you are asking without JavaScript.

answered Aug 6, 2012 at 16:15

Niet the Dark Absol

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8 Comments

bob12345 Over a year ago

@Sable i know but when u go choose month 02(feb) the day drop down should be limited to 29 only

Mr. Llama Over a year ago

Kolink's statement still stands. Once PHP sends the page to the browser, it can no longer modify it. That includes changing the day options after a user selects a month. If you really can't use JavaScript, then you'll have to do the date selection in two steps: one for month/year, one for day.

Matt Over a year ago

@Kolink OP can do it, but it would require a page refresh.

Niet the Dark Absol Over a year ago

@Matt And what would trigger the page refresh?

Matt Over a year ago

oncli... ah i see what you did there!

|

Dovydas Navickas · Accepted Answer · 2012-08-06 16:17:07Z

0

Without Javascript it is just impossible to do.

answered Aug 6, 2012 at 16:17

Dovydas Navickas

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