Special characters with Ajax and MySQL - php

Question

I have a MySQL database encoded with the default characterset UTF8. I have also a PHP code encoded with the same charset meta charset="UTF-8".
My connection to the database is configured to use UTF8 too
new PDO("mysql:host=" .$host. ";dbname=".$database,$username,$password,
array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));
But I have a problem when I use Ajax to get the content of a textbox and insert it into the database.
If I do not use special characters it works fine but when I use a quote or something everything stops working.
I tried to use UTF8_encode and UTF8_decode but nothing changed
EDIT
PHP
...
<meta charset="UTF-8">
...
<textarea class="commentBox" id="<?php echo $id_case;?>"></textarea>
<button class="saveComment" id="<?php echo $id_case;?>"> Save comment </button>
//id_case is different for each textarea
Javascript
$('.saveComment').click(function()
{
var idComment = this.id;
var content = $('#'+idComment+'.commentBox').val();
add_comment(idComment, content);
});
function add_comment(case_id, content)
{
$.post("../functions/ajax/add_comment.php",
{
id_case: case_id,
content: content
},
function(data,status)
{
alert("It worked !");
console.log("Function add_comment : "+status);
});
}
add_comment.php
<?php
if(isset($_POST['id_case'], $_POST['content']))
{
$case = $_POST['id_case'];
$content = $_POST['content'];
}
else
{
echo "Error during sending data to [add_comment.php]";
}
if($db != null)
{
try
{
$sql = ("UPDATE cases SET progress_remarks = '$content' WHERE id_cases = $case");
$result = $db->exec($sql);
echo $content;
}
catch(PDOException $e)
{
echo $sql . "<br>" . $e->getMessage();
}
}
else echo "Erreur interne (fill_progress.php)";
?>
My database connection is done somewhere else but looks like this
$this->con = new PDO("mysql:host=" .$host. ";dbname=".$database,$username,$password,
array(PDO::MYSQL_ATTR_INIT_COMMAND => "SET NAMES utf8"));

Answer 1

when I use a quote or something everything stops working.
It is unclear whether the problem is (1) just an escaping issue, or (2) also a utf8 issue.
Since PDO has a builtin way to take care of escaping, use it:
$sql = ("UPDATE cases SET progress_remarks = ? WHERE id_cases = $case");
$result = $db->exec($sql, $content);
This is probably the preferred way to set the charset with PDO: $db = new PDO('dblib:host=host;dbname=db;charset=UTF-8', $user, $pwd);
meta charset="UTF-8" refers to the tag in HTML, not PHP or MySQL.
SHOW CREATE TABLE -- Is the column in question declared CHARACTER SET utf8?