How would I query just the title of a document collection using mongo in PHP?

See more:

PHP

MongoDB

I am working on a regex search box which will return only document titles from my document collection.

It may seem a simple task, however, as I am a beginner, I am struggling on completing this task.

This is my code:

<?php
//error_reporting(0);
    require 'view/header.php';
    include 'config.php';
?>

<form action="" method="post">
    <h4>Insert a regex command below</h4>
    <!--Regex: <input type="text" name="regex"/>-->
    Title: <input type="text" name="title"/>
    <input type="submit" value="Search"/><br/><br/>
</form>

<?php
    $m = new MongoClient();
    $db = $m->selectDB("fldev");
    $collections = $db->getCollectionNames();
    $collection = $m->selectCollection('fldev', 'docs');
    //var_dump($collection);

    echo "<pre>";
    foreach ($collections as $collectionName) {
      echo "Found collection: ", $collectionName, "<br/>";
    }
    echo "</pre><br/>";
?>

<?php
    //$regex=(isset($_POST["regex"]) ? $_POST["regex"] : "");
    $title=(isset($_POST["title"]) ? $_POST["title"] : "");
    //var_dump($regex);

    //$results = $collection->findOne(array('title' => 'greeklish abstract'));

  echo "<pre>";
    var_dump($collection->findOne(array('$title' => 'greeklish abstract')));
    var_dump($collection->findOne(array('$id' => '526937f8fa96470e3944a7ef')));
  echo "</pre>";
?>

<?php
    require 'view/footer.php';
?>

I tried to just get one document from the collection however it outputs 'NULL' as in there is no document found.