Question

How can JSON be used to parse xmlhttp.responseText? I can’t seem to get textboxes populated using the parsed data. I tried using .value and .innerHTML with the dot notation with b.first and b.second used with json_encode from the loadTextBox.php file (see below), but the textboxes won’t populate.

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 doc = window.document.createElement("doc");
         var a = xmlhttp.responseText;
         var b = JSON.parse(a);
         document.getElementById("textbox").innerHTML=b.first;
         document.getElementById("textbox2").innerHTML=b.second;
      }
   }

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

loadTextBox.php code:

<?php
---Placeholder for correct DB login info---

$result = $mysql->query("SELECT column_one FROM table_one");

while ($row = $result->fetch_object())
{
   $queryResult[] = $row->present_tense;
}
$textboxValue = $queryResult[0];
$textboxValue2 = $queryResult[2];
echo json_encode(array('first'=>$textboxValue,'second'=>$textboxValue2));
?>

Answer 1

I have figured out the underlying problem. Extra tags were being sent because I had unnecessary tags in my DB info file. Those tags were being sent in the responseText with {“first”:”radim”,”second”:”radi”}. So the code pertaining to —Placeholder for correct DB login info— was wrong. I also changed .innerHTML to .value and now it works as intended.

Main page code updated:

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;
      }
   }

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