使用json_encode通过xmlhttp.responseText发送特殊字符（即caron）

Question

I'm trying to grab data with a special character (caron) from a database and send it through xmlhttp.responseText using json_encode to populate textboxes. The specific textbox associated with the data containing the special character (caron) is displaying nothing. The other textboxes are displaying correct data. I tried using the Javascript function encodeURIComponent, but only null showed in the textbox. Any help would be appreciated.

Main page code:

function loadDoc()
{
   var xmlhttp;

   // code for IE7+, Firefox, Chrome, Opera, Safari
   if (window.XMLHttpRequest)
   {
      xmlhttp=new XMLHttpRequest();
   }
   // code for IE6, IE5
   else
   {
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
   }

   xmlhttp.onreadystatechange=function()
   {
      if (xmlhttp.readyState==4 && xmlhttp.status==200)
      {
         var a = JSON.parse(xmlhttp.responseText);
         document.getElementById("textbox").value=a.first;
         document.getElementById("textbox2").value=a.second;
         document.getElementById("textbox3").value=a.third;
         document.getElementById("textbox4").value=a.fourth;
         document.getElementById("textbox5").value=a.fifth;
         document.getElementById("textbox6").value=a.sixth;
      }
   }

   xmlhttp.open("GET","loadTextBox.php?id=4",true);
   xmlhttp.send();
}

loadTextBox.php code:

<?php
header("Content-type: application/json");

---Placeholder for correct DB login info---

$result = $mysql->query(---Placeholder for correct SQL query---);

while ($row = $result->fetch_object())
{
   $queryResult[] = $row->colun_one;
}
$textboxValue = $queryResult[0];
$textboxValue2 = $queryResult[1];
$textboxValue3 = $queryResult[2];
$textboxValue4 = $queryResult[3];
$textboxValue5 = $queryResult[4];
$textboxValue6 = $queryResult[5];
echo    
json_encode(array('first'=>$textboxValue,'second'=>$textboxValue2,
'third'=>$textboxValue3,'fourth'=>$textboxValue4,'fifth'=>$textboxValue5,
'sixth'=>$textboxValue6));
?>

Answer 1

Adding in the line $mysql->query("SET CHARACTER SET 'utf8'"); inside loadTextBox.php after connecting to the DB and before the SQL query fixed it.