ajax + php живой поиск непонятки

<?php
 
// Credentials
$dbhost = "localhost";
$dbname = "---";
$dbuser = "---";
$dbpass = "---";
 
//  Connection
global $tutorial_db;
 
$tutorial_db = new mysqli();
$tutorial_db->connect($dbhost, $dbuser, $dbpass, $dbname);
$tutorial_db->set_charset("utf8");
 
//  Check Connection
if ($tutorial_db->connect_errno) {
    printf("Connect failed: %s\n", $tutorial_db->connect_error);
    exit();
}
 
 
// Define Output HTML Formating
$html = '';
$html .= '<li class="result">';
$html .= '<a target="_blank" href="urlString">';
$html .= '<h3>nameString</h3>';
$html .= '<h4>functionString</h4>';
$html .= '</a>';
$html .= '</li>';
 
// Get Search
$search_string = preg_replace("/[^A-Za-zА-Яа-я0-9]/", " ", $_POST['query']);
$search_string = $tutorial_db->real_escape_string($search_string);
 
// Check Length More Than One Character
if (strlen($search_string) >= 1 && $search_string !== ' ') {
    // Build Query
    $query = 'SELECT * FROM cat_common_props WHERE  title LIKE "%'.$search_string.'%"';
 
    // Do Search
    $result = $tutorial_db->query($query);
    while($results = $result->fetch_array()) {
        $result_array[] = $results;
    }
 
    // Check If We Have Results
    if (isset($result_array)) {
        foreach ($result_array as $result) {
 
            // Format Output Strings And Hightlight Matches
            $display_function = preg_replace("/".$search_string."/i", "<b class='highlight'>".$search_string."</b>", $result['url']);
            $display_name = preg_replace("/".$search_string."/i", "<b class='highlight'>".$search_string."</b>", $result['title']);
            $display_url = 'http://php.net/manual-lookup.php?pattern='.urlencode($result['function']).'&lang=en';
 
            // Insert Name
            $output = str_replace('nameString', $display_name, $html);
 
            // Insert Function
            $output = str_replace('functionString', $display_function, $output);
 
            // Insert URL
            $output = str_replace('urlString', $display_url, $output);
 
            // Output
            echo($output);
        }
    }else{
 
        // Format No Results Output
        $output = str_replace('urlString', 'javascript:void(0);', $html);
        $output = str_replace('nameString', '<b>No Results Found.</b>', $output);
        $output = str_replace('functionString', 'Sorry :(', $output);
 
        // Output
        echo($output);
    }
}
 
 
/*
// Build Function List (Insert All Functions Into DB - From PHP)
 
// Compile Functions Array
$functions = get_defined_functions();
$functions = $functions['internal'];
 
// Loop, Format and Insert
foreach ($functions as $function) {
    $function_name = str_replace("_", " ", $function);
    $function_name = ucwords($function_name);
 
    $query = '';
    $query = 'INSERT INTO search SET id = "", function = "'.$function.'", name = "'.$function_name.'"';
 
    $tutorial_db->query($query);
}
*/
?>