输入值是否可以与HTML表单中的占位符相同？

I have an HTML form that accepts a CVV number as one of the field items -

<label for="cvv">CVV</label>
<input type="text" placeholder="123" maxlength="3" id="cvv" name="cvv">

As you can see, it has a placeholder="123". I'm entering the CVV number into my database as part of an array -

$pay = array(
    'cardno' => $cardno,
    'exp' => $this->input->post('exp'),
    'cvv' => $this->input->post('cvv'),
    'name' => $this->input->post('name'),
    'org' => $this->session->userdata['user_data']['org']
    );
$this->db->insert('payment', $pay);

I'm able to enter any CVV value into the database except 123 which is the same as the placeholder value. I keep getting the following error -

Error Number: 1366

Incorrect integer value: '' for column 'cvv' at row 1

INSERT INTO `payment` (`cardno`, `exp`, `cvv`, `name`, `org`) VALUES ('6547893210258135', '04/20', '', 'Joe Bloggs', '15')

Filename: C:\xampp\htdocs\ci_redesign_newdb\system\database\DB_driver.php

Line Number: 330

When I print the $pay array before inserting it into the database, with cvv as 123, the CVV field is empty -

Array ( [cardno] => 6547893210258135 [exp] => 04/20 [cvv] => [name] => Joe Bloggs [org] => 15 )

However, if I change the CVV value to anything else, the CVV field gets populated -

Array ( [cardno] => 6547893210258135 [exp] => 04/20 [cvv] => 103 [name] => Joe Bloggs [org] => 15 )

And since that field gets populated, I'm able to enter it into the database without any errors. What could be the reason the form isn't accepting a value that is the same as the field's placeholder, i.e., 123 in this case?

EDIT 1

This problem seems to be present for all input fields in the form. I only noticed it for cvv since I happened to enter 123 as a test. So, it looks like all the fields where the entered input value is the same as the placeholder value are not being input.

EDIT 2 - PROBLEM SOURCE

It looks like the problem is originating from the jQuery source file version 2.0.3. I commented out the file in my code -

<script src='<?php echo base_url(); ?>assets/js/jquery-2.0.3.min.js'></script>

and I was able to post the input values which were the same as my placeholder -

Array ( [cardno] => 1234567890123456 [exp] => mm/yy [cvv] => 123 [name] => Name [org] => 15 )

Is this something that can be solved by editing the jQuery source file? Should I be making such changes? Don't want to make changes that could cause problems elsewhere.

This is really weird. I'm sure there is some JavaScript code or a library you are using is causing this.

A possible way around your problem is to remove/change the placeholder attribution of your inputs right before submiting it.

For example;

<form id="yourform" name="yourform">
 <input type="text" placeholder="123" id="cvv"/>
 <div class="button" onclick="submitForm()">Submit</div>
</form>

In JS;

function submitForm(){
   document.getElementById("cvv").placeholder = "";
    //Do it for all of your input elems.

   document.yourform.submit();
}

Not sure it is going to work, and I know not the actual proper way to solve it, but would do the trick.