diff --git annotation_text/annotation_text.install annotation_text/annotation_text.install
index 9c7656a..3100210 100644
--- annotation_text/annotation_text.install
+++ annotation_text/annotation_text.install
@@ -1,6 +1,11 @@
 <?php
 
 /**
+ * @file
+ * Installation file for Annotation Text module.
+ */
+
+/**
  * Implements hook_install().
  */
 function annotation_text_install() {
@@ -8,6 +13,47 @@ function annotation_text_install() {
 }
 
 /**
+ * Implements hook_requirements().
+ */
+function annotation_text_requirements($phase) {
+  $requirements = array();
+  $t = get_t();
+
+  $requirements['annotation_textchildren']['title'] = $t('jquery.textchildren.js');
+  if (file_exists(drupal_get_path('module', 'annotation_text') . '/jquery.textchildren.js')) {
+    $requirements['annotation_textchildren']['value'] = $t('jquery.textchildren.js present');
+    $requirements['annotation_textchildren']['severity'] = REQUIREMENT_OK;
+  }
+  else {
+    // Required library wasn't found. Abort installation.
+    $requirements['annotation_textchildren']['value'] = $t('Not found');
+    // Provide a download link.
+    $requirements['annotation_textchildren']['description'] = $t('The jQuery Textchildren plugin is missing. <a href="@download">Download</a> and extract it to your <em>annotation/annotation_text</em> module directory.', array(
+      '@download' => 'http://plugins.learningjquery.com/textchildren/jquery.textchildren.js',
+    ));
+    $requirements['annotation_textchildren']['severity'] = REQUIREMENT_ERROR;
+  }
+
+  $requirements['annotation_wrapselection']['title'] = $t('jquery.wrapSelection.js');
+  if (file_exists(drupal_get_path('module', 'annotation_text') . '/jquery.wrapSelection.js')) {
+    $requirements['annotation_wrapselection']['value'] = $t('jquery.wrapSelection.js present');
+    $requirements['annotation_wrapselection']['severity'] = REQUIREMENT_OK;
+  }
+  else {
+    // Required library wasn't found. Abort installation.
+    $requirements['annotation_wrapselection']['value'] = $t('Not found');
+    // Provide a download link.
+    $requirements['annotation_wrapselection']['description'] = $t('The jQuery wrapSelection plugin is missing. <a href="@download">Download</a> and extract it to your <em>annotation/annotation_text</em> module directory.', array(
+      '@download' => 'http://plugins.jquery.com/project/wrapSelection',
+    ));
+    $requirements['annotation_wrapselection']['severity'] = REQUIREMENT_ERROR;
+  }
+
+  return $requirements;
+}
+
+
+/**
  * Implements hook_schema().
  */
 function annotation_text_schema() {