third dropdown list is not working

[Alwinaz]

I am creating three dropdown lists from mysql table. The first two lists work, but it seems to have a problem when populating the third list. When I echo the query this is what is send to the mysql table -

SELECT DISTINCT `matter_type`
FROM `legalpages`
WHERE `Claims Hub`= AND `areas`='VEREENIGING'.

it seems as if it does not post the value of the 'Claims Hub'. Here is my select_list2.php script

 

<?php


require_once('connectvars.php');


// Here add the name of the table and columns that will be used for select lists, in their order
// Add null for 'links' if you don`t want to display their data too
$table = 'legalpages';
$ar_cols = array('Claims Hub', 'areas', 'matter_type', 'phone');


$preid = 'slo_';        // a prefix used for element's ID, in which Ajax will add <select>
$col = $ar_cols[0];     // the variable used for the column that wil be selected
$re_html = '';          // will store the returned html code


// if there is data sent via POST, with index 'col' and 'wval'
if(isset($_POST['col']) && isset($_POST['wval'])) {
  // set the $col that will be selected and the value for WHERE (delete tags and external spaces in $_POST)
  $col = trim(strip_tags($_POST['col']));
  $wval = "'".trim(strip_tags($_POST['wval']))."'";
}


$key = array_search($col, $ar_cols);            // get the key associated with the value of $col in $ar_cols
$wcol = $key===0 ? $col : $ar_cols[$key-1];     // gets the column for the WHERE clause
$_SESSION['ar_cols'][$wcol] = isset($wval) ? $wval : $wcol;    // store in SESSION the column and its value for WHERE
  
// gets the next element in $ar_cols (needed in the onchange() function in <select> tag)
$last_key = count($ar_cols)-1;
$next_col = $key<$last_key ? $ar_cols[$key+1] : '';


$dbc = mysqli_connect(DB_HOST, DB_USER, DB_PASSWORD, DB_NAME);     // connect to the MySQL database


if (mysqli_connect_errno()) { exit('Connect failed: '. mysqli_connect_error()); }     // check connection


// sets an array with data of the WHERE condition (column=value) for SELECT query
for($i=1; $i<=$key; $i++) {
  $ar_where[] = '`'.$ar_cols[$i-1].'`='.$_SESSION['ar_cols'][$ar_cols[$i-1]];
}


// define a string with the WHERE condition, and then the SELECT query
$where = isset($ar_where) ? ' WHERE '. implode($ar_where, ' AND ') : '';
$sql = "SELECT DISTINCT `$col` FROM `$table`".$where;
echo $sql;
$result = $dbc->query($sql);       // perform the query and store the result


// if the $result contains at least one row
if ($result->num_rows > 0) {
  // sets the "onchange" event, which is added in <select> tag
  $onchg = $next_col!==null ? " onchange=\"ajaxReq('$next_col', this.value);\"" : '';


  // sets the select tag list (and the first <option>), if it's not the last column
  if($col!=$ar_cols[$last_key]) $re_html = $col. ': <select name="'. $col. '"'. $onchg. '><option>- - -</option>';


  while($row = $result->fetch_assoc()) {
    // if its the last column, reurns its data, else, adds data in OPTION tags
    if($col==$ar_cols[$last_key]) $re_html .= '<br/>'. $row[$col];
    else $re_html .= '<option value="'. $row[$col]. '">'. $row[$col]. '</option>';
  }


  if($col!=$ar_cols[$last_key]) $re_html .= '</select> ';        // ends the Select list
}
else { $re_html = '0 results'; }


$dbc->close();


// if the selected column, $col, is the first column in $ar_cols
if($col==$ar_cols[0]) {
  // adds html code with SPAN (or DIV for last item) where Ajax will add the select dropdown lists
  // with ID in each SPAN, according to the columns added in $ar_cols
  for($i=1; $i<count($ar_cols); $i++) {
    if($ar_cols[$i]===null) continue;
    if($i==$last_key) $re_html .= '<div id="'. $preid.$ar_cols[$i]. '"> </div>';
    else $re_html .= '<span id="'. $preid.$ar_cols[$i]. '"> </span>';
  }


  // adds the columns in JS (used in removeLists() to remove the next displayed lists when makes other selects)
  $re_html .= '<script type="text/javascript">var ar_cols = '.json_encode($ar_cols).'; var preid = "'. $preid. '";</script>';
}
else echo $re_html;
?>

I am also using this ajax script which access the above script.

// function used to remove the next lists already displayed when it chooses other options
function removeLists(colid) {
var z = 0;
// removes data in elements with the id stored in the "ar_cols" variable
// starting with the element with the id value passed in colid
for(var i=1; i<ar_cols.length; i++) {
if(ar_cols[i]==null) continue;
if(ar_cols[i]==colid) z = 1;
if(z==1) document.getElementById(preid+ar_cols[i]).innerHTML = '';
}
}

// create the XMLHttpRequest object, according browser
function get_XmlHttp() {
// create the variable that will contain the instance of the XMLHttpRequest object (initially with null value)
var xmlHttp = null;

if(window.XMLHttpRequest) { xmlHttp = new XMLHttpRequest(); } // for Forefox, IE7+, Opera, Safari
else if(window.ActiveXObject) { xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); } // IE5 or 6

return xmlHttp;
}

// sends data to a php file, via POST, and displays the received answer
function ajaxReq(col, wval) {
removeLists(col); // removes the already next selects displayed

// if the value of wval is not '- - -' and '' (the first option)
if(wval!='- - -' && wval!='') {
var request = get_XmlHttp(); // call the function with the XMLHttpRequest instance
var php_file = 'select_list2.php'; // path and name of the php file

// create pairs index=value with data that must be sent to server
var data_send = 'col='+col+'&wval='+wval;

request.open("POST", php_file, true); // set the request

document.getElementById(preid+col).innerHTML = 'Loadding...'; // display a loading notification

// adds a header to tell the PHP script to recognize the data as is sent via POST
request.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
request.send(data_send); // calls the send() method with data_send

// Check request status
// If the response is received completely, will be added into the tag with id value of "col"
request.onreadystatechange = function() {
if (request.readyState==4) {
document.getElementById(preid+col).innerHTML = request.responseText;
}
}
}
}

where did i miss something?