PHP $_POST is empty after using jquery val() on input

Question

I want to check value of input for year of birth. I have figured out that if I use jquery function val() to get value of this input, so the php post of this input will be empty. It works fine without using val(). Here you can see the important part part of code. It is not so essential ability of form, but it would be useful to check if the isn't written anything inappropriate or any mistype.

Thank you for help.

<?php
if (!empty($_POST['rn']) && isset($_POST['rn'])){
    // proceed
} else {
    echo "You haven't filled all inputs";
}
?>
<script>
$("#kontrolaButton").click(function(){
    var rok = parseInt($("#rok_nar").val(),10);
    if (rok > 1900 && rok < 2016) {
        $("#odeslatButton").trigger('click');
    };
});
</script>
<form accept-charset="utf-8" method="post" action="<?php echo htmlspecialchars($_SERVER["PHP_SELF"]);?>" class="send_form">

<input class="bold" id="rok_nar" type="text" name="rn" placeholder="Rok narození"/>
<input type="button" value="Odeslat" name="kontrola" id="kontrolaButton" /> 
<input type="submit" value="Odeslat" name="odeslat" id="odeslatButton" style="visibility: hidden;" />

</form>

Update: I have probably found the problem. I didn't write it here, because I didn't consider it as an issue. My script looks like:

$("#kontrolaButton").click(function(){
    var rok = parseInt($("#rok_nar").val(),10);
    alert(rok);
    if (rok > 1900 && rok < 2016) {
        $("#odeslatButton").trigger('click');
    };
});

After erasing the alert, the code works :/ Interesting...

nothing to prevent user submitting by keyboard here and completely bypass your click handler — charlietfl
– charlietfl, Commented Jan 25, 2016 at 23:13
also check your browser console for errors. You have several syntax problems that will be evident in your console. Those errors are preventing your code from doing anything. Always always check for errrors — charlietfl
– charlietfl, Commented Jan 25, 2016 at 23:15
@charlietfl Thank s for advice, I haven't thought about it, I will probably try it with using on submit and prevent default. Sorry for syntax typos. I have just took few parts of code, so I have rewritten it here, and made the mistakes, but at actual code it is ok :/ — Vít Horáček
– Vít Horáček, Commented Jan 25, 2016 at 23:38
It has to be something else, if I comment the jquery part checking the value of input, it works like a charm. — Vít Horáček
– Vít Horáček, Commented Jan 25, 2016 at 23:41
The code you provided works, provided you move the script down. So there is some other context that we need. Are you sure all your ID values are unique, especially rok_nar? If possible, please provide the full code. If you provide less code, then please check first that the problem reproduces with that smaller code. — trincot
– trincot, Commented Jan 25, 2016 at 23:54

Taplar · Accepted Answer · 2016-01-25 23:10:01Z

2

It looks like your trying to access an input in the dom before it is loaded. I don't see a document ready. You need to either stick your script inside a document ready so it is delayed until the dom is completely parsed, or move your logic at the bottom of your page so the elements exist by the time you try to look them up.

answered Jan 25, 2016 at 23:10

Taplar

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1 Comment

Vít Horáček Over a year ago

I have already got the script inside ready, I just haven't written it here, sorry. However I have moved it from the head to the end of thebody and also no change :/

trincot · Accepted Answer · 2016-01-26 09:51:00Z

1

You should move the script right to the end of the HTML body so that it executes when the kontrolaButton element is in the DOM.

Note that the mouse down/up or key press/release you issue to close the alert(rok); may interfere with the submission of the form. For instance, I could reproduce a problem like this: I pressed the ESC key to close the alert, and although the form submitted its data, the next page did not render; it was just a blank page. This may be very browser dependent, but on my set-up the ESC key apparently interrupts the rendering of a page.

There may be other such side effects, certainly also if you have other Javascript code on the page that responds to these key or mouse events.

edited Jan 26, 2016 at 9:51

answered Jan 25, 2016 at 23:23

trincot

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1 Comment

Vít Horáček Over a year ago

Excuse me for mistypes, but there are only here, I have rewritten it, at actual code it is written correctly.

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