Drupal使用自动完成文本字段抛出ajax错误200？

Question

In this module I'm creating i'm implementing drupal's autocomplete and it's giving me this error. I can't figure out why..

An AJAX HTTP error occurred.
HTTP Result Code: 200
Debugging information follows.
Path: http://localhost/admin/content/searchcontent/autocomplete
StatusText: OK
ResponseText: 
localhost
@import url("http://localhost/modules/system/system.base.css?mm2qoh");
@import url("http://localhost/modules/system/system.menus.css?mm2qoh");
@import url("http://localhost/modules/system/system.messages.css?mm2qoh");
@import url("http://localhost/modules/system/system.theme.css?mm2qoh");
@import url("http://localhost/misc/ui/jquery.ui.core.css?mm2qoh");
@import url("http://localhost/themes/seven/jquery.ui.theme.css?mm2qoh");
@import url("http://localhost/misc/ui/jquery.ui.autocomplete.css?mm2qoh");
@import url("http://localhost/modules/system/system.admin.css?mm2qoh");
@import url("http://localhost/sites/all/modules/customheaderimage/css/customheaderimage_style.css?mm2qoh");
@import url("http://localhost/sites/all/modules/customheaderimage/css/customheaderimage_admin_style.css?mm2qoh");
@import url("http://localhost/sites/all/modules/custom/searchcontent/searchcontent.css?mm2qoh");
@import url("http://localhost/modules/comment/comment.css?mm2qoh");
@import url("http://localhost/modules/field/theme/field.css?mm2qoh");
@import url("http://localhost/modules/node/node.css?mm2qoh");
@import url("http://localhost/modules/search/search.css?mm2qoh");
@import url("http://localhost/modules/user/user.css?mm2qoh");
@import url("http://localhost/sites/all/modules/views/css/views.css?mm2qoh");
@import url("http://localhost/sites/all/modules/coffee/css/coffee.css?mm2qoh");
@import url("http://localhost/sites/all/modules/ctools/css/ctools.css?mm2qoh");
@import url("http://localhost/modules/toolbar/toolbar.css?mm2qoh");
@import url("http://localhost/modules/shortcut/shortcut.css?mm2qoh");
@import url("http://localhost/themes/seven/reset.css?mm2qoh");
@import url("http://localhost/themes/seven/style.css?mm2qoh");
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It's just returning the page, not the json output..It does this in firefox and chrome that i've checked. Here is the rest of my code to implement it.

function searchcontent_menu() {
  $items['admin/content/searchcontent/autocomplete'] = array(
    'page_callback' => 'searchcontent_autocomplete',
    'access callback' => TRUE,
    'type' => MENU_CALLBACK,
  );
  return $items;
}

//This form code is in the form setup function
$form['searchcontent_box']['searchcontent_search'] = array(
  '#type' => 'textfield',
  '#default_value' => $keywords,
  '#weight' => -10,
  '#size' => 38,
  '#autocomplete_path' => 'admin/content/searchcontent/autocomplete',
);

function searchcontent_autocomplete($string = '') {
  $items = array();
  $items['about'] = 'about';
  $items['contact'] = 'contact';
  drupal_json_output($items);
}

I explicitly set the items for testing so that there was no issue with my query. Can anyone find the error that is causing this?

Thanks.