Ajax发送日期数据

Question

I have a problem with my jquery script, it is returning error when I try to send the date value from my form, when I leave it in blank, it doesn't show me an error.

<div class="field-wrap">
    <input type="date" name="fecha_nacimiento" required autocomplete="off" maxlength="30" placeholder="Fecha de nacimiento">Fecha de nacimiento</input>
</div> 
<script>
$(function(){
    $('#entrarBt').click(function(){
        $.ajax({
            url: 'registro_dpb.php',
            type: 'POST', // GET or POST               
            data: $("#miForm").serialize(), // will be in $_POST on PHP side

            success: function(data) { // data is the response from your php script
                // This function is called if your AJAX query was successful
                alert("Response is: " + data);
            },
            error: function() {
                // This callback is called if your AJAX query has failed
                alert("Error!");
            }
        });
    });
});
</script>

Answer 1

Your problem was pretty subtile... Making it hard to find.
But the solution is really simple.

You use a <button> inside a <form> which is absolutely correct.

But you have to know that in HTML5, if the type of a <button> is not explicitly defined as "button", its default type is "submit".

Reference here.

This was the issue...
Since you want to submit using an ajax request, which allow to receive a response without reloading the page, you have to "prevent" this normal behavior of a <button>.

The submit made by the button was not sent to your PHP script, but to your HTML page (there was no other action defined in the <form> tag, so the default is "self".
So the page reloads... Making your ajax request to fail.

So there is two ways to fix this:

1: Define the button type as "button":

<button type="button" id="entrarBt" [+ other attributes]>Entrar</button>

or
2: Prevent this default behavior using prevent.default() in you click handler.

$('#entrarBt').click(function(e){
  e.preventDefault();

  $.ajax({
      //...

I think the second one is more evident for another programmer who could review your code, but the first is ok too.

---

For the benefit of the other SO readers:
We (me and Javier) checked almost every other error possibilities in chat.
I finally found the cause when, for a test, I commented out the whole ajax block and then noticed that the page was still submitting.

Fixing this completely resolved the issue.

This is a tricky thing to absolutely know!
In short, a <button> within a HTML5 <form> is a submit by default!