diff --git a/amp.admin.inc b/amp.admin.inc
index cd9d1f9..268f88d 100644
--- a/amp.admin.inc
+++ b/amp.admin.inc
@@ -9,6 +9,7 @@
  * Form constructor for the AMP administration form.
  *
  * @ingroup forms
+ *
  * @see amp_admin_form_validate()
  * @see amp_admin_form_submit()
  */
@@ -33,7 +34,10 @@ function amp_admin_form($form, &$form_state) {
     '#default_value' => variable_get('amp_google_analytics_id'),
     '#size' => 15,
     '#maxlength' => 20,
-    '#description' => t('This ID is unique to each site you want to track separately, and is in the form of UA-xxxxxxx-yy. To get a Web Property ID, <a href="@analytics">register your site with Google Analytics</a>, or if you already have registered your site, go to your Google Analytics Settings page to see the ID next to every site profile. <a href="@webpropertyid">Find more information in the documentation</a>.', array('@analytics' => 'http://www.google.com/analytics/', '@webpropertyid' => url('https://developers.google.com/analytics/resources/concepts/gaConceptsAccounts', array('fragment' => 'webProperty')))),
+    '#description' => t('This ID is unique to each site you want to track separately, and is in the form of UA-xxxxxxx-yy. To get a Web Property ID, <a href="@analytics">register your site with Google Analytics</a>, or if you already have registered your site, go to your Google Analytics Settings page to see the ID next to every site profile. <a href="@webpropertyid">Find more information in the documentation</a>.', array(
+      '@analytics' => 'http://www.google.com/analytics/',
+      '@webpropertyid' => url('https://developers.google.com/analytics/resources/concepts/gaConceptsAccounts', array('fragment' => 'webProperty'))
+    )),
   );
   $form['amp_google_adsense_id'] = array(
     '#type' => 'textfield',
@@ -66,8 +70,10 @@ function amp_admin_form($form, &$form_state) {
     '#title' => t('amp-pixel domain name'),
     '#default_value' => variable_get('amp_pixel_domain_name'),
     '#description' => t('The domain name where the tracking pixel will be loaded: do not include http or https.'),
-    '#states' => array('visible' => array(
-      ':input[name="amp_pixel"]' => array('checked' => TRUE))
+    '#states' => array(
+      'visible' => array(
+        ':input[name="amp_pixel"]' => array('checked' => TRUE)
+      )
     ),
   );
   $form['pixel_group']['amp_pixel_query_string'] = array(
@@ -75,8 +81,10 @@ function amp_admin_form($form, &$form_state) {
     '#title' => t('amp-pixel query path'),
     '#default_value' => variable_get('amp_pixel_query_string'),
     '#description' => t('The path at the domain where the GET request will be received, e.g. "pixel" in example.com/pixel?RANDOM.'),
-    '#states' => array('visible' => array(
-      ':input[name="amp_pixel"]' => array('checked' => TRUE))
+    '#states' => array(
+      'visible' => array(
+        ':input[name="amp_pixel"]' => array('checked' => TRUE)
+      )
     ),
   );
   $form['pixel_group']['amp_pixel_random_number'] = array(
@@ -84,8 +92,10 @@ function amp_admin_form($form, &$form_state) {
     '#title' => t('Random number'),
     '#default_value' => variable_get('amp_pixel_random_number'),
     '#description' => t('Use the special string RANDOM to add a random number to the URL if required. Find more information in the <a href="https://github.com/ampproject/amphtml/blob/master/spec/amp-var-substitutions.md#random">amp-pixel documentation</a>.'),
-    '#states' => array('visible' => array(
-      ':input[name="amp_pixel"]' => array('checked' => TRUE))
+    '#states' => array(
+      'visible' => array(
+        ':input[name="amp_pixel"]' => array('checked' => TRUE)
+      )
     ),
   );
 
@@ -102,26 +112,23 @@ function amp_admin_form($form, &$form_state) {
   $form['amp_library']['amp_library_warnings_display'] = array(
     '#type' => 'checkbox',
     '#title' => t('<em>Debugging</em>: Show AMP PHP library warnings in all amp text formatters for all users'),
-    '#default_value' => variable_get('amp_library_warnings_display', false),
-    '#description' => t('<ul><li>if you only want to see amp formatter specific warning for one node add '
-            . 'query "warnfix" at end of a node url. e.g. <strong>node/12345?amp&warnfix</strong></li>'
-            . '<li>If the Debugging checkbox value is changed upon save, the Drupal cache will be cleared</li>'),
+    '#default_value' => variable_get('amp_library_warnings_display', FALSE),
+    '#description' => t('<ul><li>if you only want to see amp formatter specific warning for one node add query "warnfix" at end of a node url. e.g. <strong>node/12345?amp&warnfix</strong></li> <li>If the Debugging checkbox value is changed upon save, the Drupal cache will be cleared</li>'),
   );
 
   $form['#submit'] = array('amp_admin_form_submit');
   return system_settings_form($form);
 }
 /**
- * Submit handler for the amp_admin_form
- * Clears the Drupal cache if the AMP Library warnings display checkbox value is changed
- * 
- * @param type $form
- * @param type $form_state
+ * Submit handler for the amp_admin_form().
+ *
+ * Clears the Drupal cache if the AMP Library warnings display checkbox
+ * value is changed.
  */
 function amp_admin_form_submit($form, &$form_state) {
-  if (variable_get('amp_library_warnings_display', false) !== $form_state['values']['amp_library_warnings_display']) {
+  if (variable_get('amp_library_warnings_display', FALSE) !== $form_state['values']['amp_library_warnings_display']) {
     cache_clear_all();
-    drupal_set_message(t('AMP Library debugging checkbox changed. Cleared cache.'));    
+    drupal_set_message(t('AMP Library debugging checkbox changed. Cleared cache.'));
   }
 }
 
@@ -199,7 +206,7 @@ function amp_get_enabled_types() {
  * Helper function to retrieve a formatted list of AMP-enabled content types.
  */
 function amp_get_formatted_status_list() {
-  $enabled_types = null !== amp_get_enabled_types() ? amp_get_enabled_types() : array();
+  $enabled_types = NULL !== amp_get_enabled_types() ? amp_get_enabled_types() : array();
   $node_types = node_type_get_names();
   $node_status_list = array();
   foreach ($node_types as $bundle => $label) {
diff --git a/amp.info b/amp.info
index ef5155b..39b22d4 100644
--- a/amp.info
+++ b/amp.info
@@ -1,4 +1,5 @@
 name = Accelerated Mobile Pages (AMP)
 description = Google AMP integration
+dependencies[] = libraries (>=2.x)
 core = 7.x
 configure = admin/config/content/amp
diff --git a/amp.install b/amp.install
index 94232e3..302687f 100644
--- a/amp.install
+++ b/amp.install
@@ -10,14 +10,32 @@
  */
 function amp_requirements($phase) {
   $requirements = array();
-  if ($phase == 'install' || $phase == 'runtime') {
-    //if (empty(drupal_get_library('amp'))) {
-      //$requirements['amp_library'] = array(
-        //'title' => t('AMP'),
-        //'description' => t('The AMP module requires the PHP <a href="@library">AMP library</a>.', array('@library' => 'https://github.com/Lullabot/amp-library')),
-        //'severity' => REQUIREMENT_ERROR,
-      //);
-    //}
+  if ($phase == 'runtime') {
+    $t = get_t();
+    $library = libraries_detect('amp-library');
+    $error_type = isset($library['error']) ? drupal_ucfirst($library['error']) : '';
+    $error_message = isset($library['error message']) ? $library['error message'] : '';
+    if (empty($library['installed'])) {
+      $requirements['amp-library'] = array(
+        'title' => $t('AMP Library'),
+        'value' => $t('@e', array('@e' => $error_type)),
+        'severity' => REQUIREMENT_ERROR,
+        'description' => $t('!error The AMP module requires the PHP <a href="@library">AMP library</a>. Extract the archive and place the !path directory in the sites/all/libraries directory on your server.', array(
+          '!error' => $error_message,
+          '@library' => $library['download url'],
+          '!path' => $library['path']
+        )),
+      );
+    }
+    else {
+      $requirements['amp-library'] = array(
+        'title' => $t('AMP Library'),
+        'severity' => REQUIREMENT_OK,
+        'value' => $library['version'],
+      );
+    }
+  }
+  elseif ($phase == 'install') {
     $themes = list_themes();
     if (empty($themes['amptheme']) || empty($themes['amptheme']->status)) {
       $requirements['amptheme'] = array(
diff --git a/amp.module b/amp.module
index 4cde3d6..52e53fa 100644
--- a/amp.module
+++ b/amp.module
@@ -5,7 +5,7 @@
  * Contains amp.module.
  */
 
-require_once dirname(__FILE__).'/amp.admin.inc';
+require_once dirname(__FILE__) . '/amp.admin.inc';
 
 use Lullabot\AMP\AMP;
 
@@ -49,35 +49,61 @@ function amp_menu() {
 }
 
 /**
- * Test the AMP Library
- * @return type
+ * Implements hook_libraries_info().
+ */
+function amp_libraries_info() {
+  $libraries['amp-library'] = array(
+    'name' => 'AMP Library',
+    'vendor url' => 'https://github.com/Lullabot/amp-library',
+    'download url' => 'https://github.com/Lullabot/amp-library/archive/master.zip',
+    'version arguments' => array(
+      'file' => 'src/Spec/validator-generated.php',
+      'pattern' => '@([0-9]+[.]+[0-9])@',
+      'lines' => 956,
+      'cols' => 30,
+    ),
+    'files' => array(
+      'php' => array(
+        'amp-console.php',
+      ),
+    ),
+  );
+
+  return $libraries;
+}
+
+/**
+ * Test the AMP Library.
+ *
+ * @return array
+ *    The markup of the library test.
  */
 function amp_library_test() {
-    $html_header = PHP_EOL . PHP_EOL . 'OUTPUT HTML'. PHP_EOL;
-    $html_header .= '-------------' . PHP_EOL;
-    $html = '<p><a href="javascript:run();">Run</a></p>' . PHP_EOL .
-    '<p><a style="margin: 2px;" href="http://www.cnn.com" target="_parent">CNN</a></p>' . PHP_EOL .
-    '<p><a href="http://www.bbcnews.com" target="_blank">BBC</a></p>' . PHP_EOL .
-    '<p><INPUT type="submit" value="submit"></p>' . PHP_EOL .
-    '<p>This is a <!-- test comment -->sample <div onmouseover="hello();">sample</div> paragraph</p>';
-
-    $amp = _amp_create_amp_converter();
-    $amp->loadHtml($html);
-    $amp_html = htmlspecialchars($amp->convertToAmpHtml());
-    $original_html = PHP_EOL . PHP_EOL . 'ORIGINAL TEST HTML INPUT'. PHP_EOL;
-    $original_html .=                    '-------------------------' . PHP_EOL;
-    $original_html .= htmlspecialchars($html);
-    return array(
-        '#type' => 'markup',
-        '#markup' => "<h3>The Library is working fine</h3><pre>$html_header $amp_html $original_html" .  $amp->warningsHumanHtml() . "</pre>"
-    );
+  $html_header = PHP_EOL . PHP_EOL . 'OUTPUT HTML' . PHP_EOL;
+  $html_header .= '-------------' . PHP_EOL;
+  $html = '<p><a href="javascript:run();">Run</a></p>' . PHP_EOL .
+  '<p><a style="margin: 2px;" href="http://www.cnn.com" target="_parent">CNN</a></p>' . PHP_EOL .
+  '<p><a href="http://www.bbcnews.com" target="_blank">BBC</a></p>' . PHP_EOL .
+  '<p><INPUT type="submit" value="submit"></p>' . PHP_EOL .
+  '<p>This is a <!-- test comment -->sample <div onmouseover="hello();">sample</div> paragraph</p>';
+
+  $amp = _amp_create_amp_converter();
+  $amp->loadHtml($html);
+  $amp_html = htmlspecialchars($amp->convertToAmpHtml());
+  $original_html = PHP_EOL . PHP_EOL . 'ORIGINAL TEST HTML INPUT' . PHP_EOL;
+  $original_html .= '-------------------------' . PHP_EOL;
+  $original_html .= htmlspecialchars($html);
+  return array(
+    '#type' => 'markup',
+    '#markup' => "<h3>The Library is working fine</h3><pre>$html_header $amp_html $original_html" . $amp->warningsHumanHtml() . "</pre>"
+  );
 }
 
 /**
  * Implements hook_theme().
  */
 function amp_theme() {
-  $theme =  array(
+  $theme = array(
     'amp_ad' => array(
       'variables' => array(
         'adtype' => NULL,
@@ -254,7 +280,7 @@ function amp_preprocess_amp_video(&$variables) {
  * Implements hook_element_info().
  */
 function amp_element_info() {
-  // AMP Analytics element
+  // AMP Analytics element.
   $types['amp_analytics'] = array(
     '#account' => NULL,
     '#analytics_attributes_array' => [],
@@ -266,16 +292,16 @@ function amp_element_info() {
 }
 
 /**
- * #pre_render callback to render amp_analytics with js library added to head.
+ * The #pre_render callback to render amp_analytics with js library added to head.
  *
- * @param $elements
+ * @param array $element
  *   A render array for amp analytics elements.
  *
- * @return
+ * @return array $element
  *   The passed-in element with the js library necessary for the amp-analytics
  *   element added to head.
  */
-function amp_pre_render_amp_analytics($element) {
+function amp_pre_render_amp_analytics(array $element) {
   $head_js = array(
     '#tag' => 'script',
     '#type' => 'html_tag',
@@ -311,7 +337,7 @@ function amp_is_amp_request() {
   // Get current URL.
   $current_url = url(current_path(), array('absolute' => TRUE));
 
-  // Check if URL contains the amp parameter
+  // Check if URL contains the amp parameter.
   if (isset($_GET['amp'])) {
     // Get system path.
     $system_path = drupal_lookup_path('source', $path);
@@ -500,11 +526,11 @@ function amp_block_info() {
   $block_ids = array(1, 2, 3, 4);
   foreach ($block_ids as $block_id) {
     $blocks['amp_google_adsense_' . $block_id] = array(
-      'info' => t('AMP Google Adsense ' . $block_id),
+      'info' => t('AMP Google Adsense @block_id', array('@block_id' => $block_id)),
       'cache' => DRUPAL_NO_CACHE,
     );
     $blocks['amp_google_doubleclick_' . $block_id] = array(
-      'info' => t('AMP Google DoubleClick for Publishers ' . $block_id),
+      'info' => t('AMP Google DoubleClick for Publishers @block_id', array('@block_id' => $block_id)),
       'cache' => DRUPAL_NO_CACHE,
     );
   }
@@ -644,8 +670,8 @@ function amp_block_view($delta = '') {
 }
 
 /**
-* Implements hook_field_formatter_info().
-*/
+ * Implements hook_field_formatter_info().
+ */
 function amp_field_formatter_info() {
   return array(
     'amp_text' => array(
@@ -684,7 +710,12 @@ function amp_field_formatter_info() {
       'label' => t('AMP image'),
       'description' => t('Display an AMP image file.'),
       'field types' => array('image'),
-      'settings' => array('image_style' => '', 'image_link' => '', 'amp_layout' => 'responsive', 'amp_fixed_height' => '300'),
+      'settings' => array(
+        'image_style' => '',
+        'image_link' => '',
+        'amp_layout' => 'responsive',
+        'amp_fixed_height' => '300'
+      ),
     ),
     'amp_iframe' => array(
       'label' => t('AMP iframe'),
@@ -756,8 +787,8 @@ function amp_field_formatter_settings_form($field, $instance, $view_mode, $form,
       '#type' => 'textfield',
       '#states' => array(
         'visible' => array(
-          ':input[name="fields[' .$field['field_name'] . '][settings_edit_form][settings][amp_layout]"]' =>
-            array('value' => 'fixed-height'))
+          ':input[name="fields[' . $field['field_name'] . '][settings_edit_form][settings][amp_layout]"]' => array('value' => 'fixed-height')
+        )
       ),
       '#size' => 10,
       '#default_value' => $settings['amp_fixed_height'],
@@ -803,7 +834,7 @@ function amp_field_formatter_settings_summary($field, $instance, $view_mode) {
   }
 
   if (strpos($display['type'], 'amp_video') !== FALSE) {
-    $summary[] = t('Dimensions for aspect ratio: @width' . 'px x @height' . 'px', array('@width' => $settings['amp_video_width'], '@height' => $settings['amp_video_height']));
+    $summary[] = t('Dimensions for aspect ratio: @width x @height', array('@width' => $settings['amp_video_width'] . 'px', '@height' => $settings['amp_video_height'] . 'px'));
   }
 
   if (strpos($display['type'], 'amp_image') !== FALSE) {
@@ -832,7 +863,7 @@ function amp_field_formatter_settings_summary($field, $instance, $view_mode) {
     $layout_setting = $settings['amp_layout'];
 
     if (isset($layout_options[$layout_setting])) {
-      $summary[] =  t('Layout: @setting', array('@setting' => $layout_options[$layout_setting]));
+      $summary[] = t('Layout: @setting', array('@setting' => $layout_options[$layout_setting]));
 
       if ($layout_options[$layout_setting] === 'fixed-height') {
         $summary[] = t('Fixed height: @height', array('@height' => $settings['amp_fixed_height']));
@@ -869,7 +900,7 @@ function amp_field_formatter_view($entity_type, $entity, $field, $instance, $lan
         $output = _text_sanitize($instance, $langcode, $item, 'value');
         $amp_content = _amp_convert_markup_to_amp($output);
         $element[$delta] = array('#markup' => $amp_content['amp_markup']);
-        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', false)) {
+        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', FALSE)) {
           $element[$delta]['#markup'] .= '<pre>' . $amp_content['amp_warnings'] . '</pre>';
         }
         _amp_add_component_libraries($amp_content['amp_components']);
@@ -884,7 +915,7 @@ function amp_field_formatter_view($entity_type, $entity, $field, $instance, $lan
         }
         $amp_content = _amp_convert_markup_to_amp($output);
         $element[$delta] = array('#markup' => $amp_content['amp_markup']);
-        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', false)) {
+        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', FALSE)) {
           $element[$delta]['#markup'] .= '<pre>' . $amp_content['amp_warnings'] . '</pre>';
         }
         _amp_add_component_libraries($amp_content['amp_components']);
@@ -902,7 +933,7 @@ function amp_field_formatter_view($entity_type, $entity, $field, $instance, $lan
         }
         $amp_content = _amp_convert_markup_to_amp($output);
         $element[$delta] = array('#markup' => $amp_content['amp_markup']);
-        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', false)) {
+        if (isset($_GET['warnfix']) || variable_get('amp_library_warnings_display', FALSE)) {
           $element[$delta]['#markup'] .= '<pre>' . $amp_content['amp_warnings'] . '</pre>';
         }
         _amp_add_component_libraries($amp_content['amp_components']);
@@ -977,7 +1008,8 @@ function _amp_get_layouts() {
 /**
  * Use AMP class from library for conversion of text to AMP HTML.
  *
- * @return AMP
+ * @return object
+ *   The AMP object.
  */
 function _amp_create_amp_converter() {
   return new AMP();
@@ -989,6 +1021,7 @@ function _amp_create_amp_converter() {
  *
  * @param string $markup
  *   The markup to be converted.
+ *
  * @return array $amp_content
  *   An array containing the following:
  *   - amp_markup: The AMP HTML.
@@ -1013,11 +1046,11 @@ function _amp_convert_markup_to_amp($markup) {
 function _amp_add_component_libraries(array $components) {
   $component_definitions = _amp_get_amp_js();
 
-  /**
+  /*
    * @var string $component_name
    * @var string $component_url
    */
-  foreach($components as $component_name => $component_url) {
+  foreach ($components as $component_name => $component_url) {
     if (isset($component_definitions[$component_name])) {
       $element = array(
         '#tag' => 'script',
diff --git a/templates/amp-pixel.tpl.php b/templates/amp-pixel.tpl.php
index e9a0565..98988c3 100644
--- a/templates/amp-pixel.tpl.php
+++ b/templates/amp-pixel.tpl.php
@@ -7,7 +7,7 @@
  * Available variables:
  * - domain: The domain name for the amp-pixel.
  * - query_string: The path for the query string.
- * - subs: An array of possible variable substitutions
+ * - subs: An array of possible variable substitutions.
  *
  * @see template_preprocess_amp_pixel()
  */
@@ -15,114 +15,143 @@
 <?php if (!empty($domain) && !empty($query_string)): ?>
   <?php
     $src = 'https://' . $domain . '/' . $query_string . '?';
-    $activeSubs = array();
+    $active_subs = array();
 
-    foreach ($subs as $sub => $subDetails) {
-      if ($subDetails['active'] === TRUE) {
-        $activeSubs = array_merge($activeSubs, array($sub => $subDetails));
-      }
-    }
+    foreach ($subs as $sub => $sub_details):
+      if ($sub_details['active'] === TRUE):
+        $active_subs = array_merge($active_subs, array($sub => $sub_details));
+      endif;
+    endforeach;
   ?>
 
-  <?php if (($activeSubCount = count($activeSubs)) !== 0): ?>
+  <?php if (($active_sub_count = count($active_subs)) !== 0): ?>
     <?php
-      $activeSubKeys = array_keys($activeSubs);
-      for ($i = 0; $i < $activeSubCount; $i++) {
-        $activeKey = $activeSubKeys[$i];
-        switch ($activeKey) {
+      $active_sub_keys = array_keys($active_subs);
+      for ($i = 0; $i < $active_sub_count; $i++):
+        $active_key = $active_sub_keys[$i];
+        switch ($active_key):
           case 'AMPDOC_HOST':
-            $src = $src . 'host=' . $activeKey;
+            $src = $src . 'host=' . $active_key;
             break;
+
           case 'AMPDOC_URL':
-            $src = $src . 'ref=' . $activeKey;
+            $src = $src . 'ref=' . $active_key;
             break;
+
           case 'CANONICAL_HOST':
-            $src = $src . 'host=' . $activeKey;
+            $src = $src . 'host=' . $active_key;
             break;
+
           case 'CANONICAL_PATH':
-            $src = $src . 'path=' . $activeKey;
+            $src = $src . 'path=' . $active_key;
             break;
+
           case 'CANONICAL_URL':
-            $src = $src . 'href=' . $activeKey;
+            $src = $src . 'href=' . $active_key;
             break;
+
           case 'SOURCE_URL':
-            $src = $src . 'href=' . $activeKey;
+            $src = $src . 'href=' . $active_key;
             break;
+
           case 'SOURCE_HOST':
-            $src = $src . 'host=' . $activeKey;
+            $src = $src . 'host=' . $active_key;
             break;
+
           case 'DOCUMENT_CHARSET':
-            $src = $src . 'charSet=' . $activeKey;
+            $src = $src . 'charSet=' . $active_key;
             break;
+
           case 'DOCUMENT_REFERRER':
-            $src = $src . 'referrer=' . $activeKey;
+            $src = $src . 'referrer=' . $active_key;
             break;
+
           case 'TITLE':
-            $src = $src . 'title=' . $activeKey;
+            $src = $src . 'title=' . $active_key;
             break;
+
           case 'VIEWER':
-            $src = $src . 'viewer=' . $activeKey;
+            $src = $src . 'viewer=' . $active_key;
             break;
+
           case 'CONTENT_LOAD_TIME':
-            $src = $src . 'contentLoadTime=' . $activeKey;
+            $src = $src . 'contentLoadTime=' . $active_key;
             break;
+
           case 'DOMAIN_LOOKUP_TIME':
-            $src = $src . 'domainLookupTime=' . $activeKey;
+            $src = $src . 'domainLookupTime=' . $active_key;
             break;
+
           case 'DOM_INTERACTIVE_TIME':
-            $src = $src . 'domInteractiveTime=' . $activeKey;
+            $src = $src . 'domInteractiveTime=' . $active_key;
             break;
+
           case 'PAGE_DOWNLOAD_TIME':
-            $src = $src . 'pageDownloadTime=' . $activeKey;
+            $src = $src . 'pageDownloadTime=' . $active_key;
             break;
+
           case 'PAGE_LOAD_TIME':
-            $src = $src . 'pageLoadTime=' . $activeKey;
+            $src = $src . 'pageLoadTime=' . $active_key;
             break;
+
           case 'REDIRECT_TIME':
-            $src = $src . 'redirectTime=' . $activeKey;
+            $src = $src . 'redirectTime=' . $active_key;
             break;
+
           case 'SERVER_RESPONSE_TIME':
-            $src = $src . 'serverResponseTime=' . $activeKey;
+            $src = $src . 'serverResponseTime=' . $active_key;
             break;
+
           case 'TCP_CONNECT_TIME':
-            $src = $src . 'tcpConnectTime=' . $activeKey;
+            $src = $src . 'tcpConnectTime=' . $active_key;
             break;
+
           case 'AVAILABLE_SCREEN_HEIGHT':
-            $src = $src . 'availScreenHeight=' . $activeKey;
+            $src = $src . 'availScreenHeight=' . $active_key;
             break;
+
           case 'AVAILABLE_SCREEN_WIDTH':
-            $src = $src . 'availScreenWidth=' . $activeKey;
+            $src = $src . 'availScreenWidth=' . $active_key;
             break;
+
           case 'BROWSER_LANGUAGE':
-            $src = $src . 'lang=' . $activeKey;
+            $src = $src . 'lang=' . $active_key;
             break;
+
           case 'SCREEN_COLOR_DEPTH':
-            $src = $src . 'colorDepth=' . $activeKey;
+            $src = $src . 'colorDepth=' . $active_key;
             break;
+
           case 'VIEWPORT_HEIGHT':
-            $src = $src . 'viewportHeight=' . $activeKey;
+            $src = $src . 'viewportHeight=' . $active_key;
             break;
+
           case 'VIEWPORT_WIDTH':
-            $src = $src . 'viewportHeight=' . $activeKey;
+            $src = $src . 'viewportHeight=' . $active_key;
             break;
+
           case 'PAGE_VIEW_ID':
-            $src = $src . $activeKey;
+            $src = $src . $active_key;
             break;
+
           case 'RANDOM':
-            $src = $src . $activeKey;
+            $src = $src . $active_key;
             break;
+
           case 'TIMESTAMP':
-            $src = $src . 'timestamp=' . $activeKey;
+            $src = $src . 'timestamp=' . $active_key;
             break;
+
           case 'TOTAL_ENGAGED_TIME':
-            $src = $src . $activeKey;
+            $src = $src . $active_key;
             break;
-        }
 
-        if ($i < ($activeSubCount - 1)) {
+        endswitch;
+
+        if ($i < ($active_sub_count - 1)):
           $src = $src . '&';
-        }
-      }
+        endif;
+      endfor;
     ?>
 
     <amp-pixel src="<?php print $src; ?>">