<h2 id="manifest">Manifest</h2>

<p>You must declare the "history" permission
in the <a href="manifest.html">extension manifest</a>
to use the history API.
For example:</p>
<pre>{
  "name": "My extension",
  ...
  <b>"permissions": [
    "history"
  ]</b>,
  ...
}</pre>

<h2 id="transition_types">Transition types</h2>

<p>
The history API uses a <em>transition type</em> to describe
how the browser navigated to a particular URL
on a particular visit.
For example, if a user visits a page
by clicking a link on another page,
the transition type is "link".
</p>

<p>
The following table describes each transition type.
</p>

<table>
<tr>
  <th> Transition type </th> <th> Description </th>
</tr>
<tr id="tt_link">
  <td>"link"</td>
  <td>
    The user got to this page by clicking a link on another page.
  </td>
</tr>
<tr id="tt_typed">
  <td>"typed"</td>
  <td>
    The user got this page by typing the URL in the address bar.
    Also used for other explicit navigation actions.
    See also <a href="#tt_generated">generated</a>,
    which is used for cases where the user selected a choice
    that didn't look at all like a URL.
  </td>
</tr>
<tr id="tt_auto_bookmark">
  <td>"auto_bookmark"</td>
  <td>
    The user got to this page through a suggestion in the UI &mdash;
    for example, through a menu item.
  </td>
</tr>
<tr id="tt_auto_subframe">
  <td>"auto_subframe"</td>
  <td>
    Subframe navigation.
    This is any content that is automatically
    loaded in a non-top-level frame.
    For example, if a page consists of
    several frames containing ads,
    those ad URLs have this transition type.
    The user may not even realize the content in these pages
    is a separate frame, and so may not care about the URL
    (see also <a href="#tt_manual_subframe">manual_subframe</a>).
  </td>
</tr>
<tr id="tt_manual_subframe">
  <td>"manual_subframe"</td>
  <td>
    For subframe navigations that are explicitly requested by the user
    and generate new navigation entries in the back/forward list.
    An explicitly requested frame is probably more important than
    an automatically loaded frame
    because the user probably cares about the fact that
    the requested frame was loaded.
  </td>
</tr>
<tr id="tt_generated">
  <td>"generated"</td>
  <td>
    The user got to this page by typing in the address bar
    and selecting an entry that did not look like a URL.
    For example, a match might have the URL of a Google search result page,
    but it might appear to the user as "Search Google for ...".
    These are not quite the same as <a href="#tt_typed">typed</a> navigations
    because the user didn't type or see the destination URL.
    See also <a href="#tt_keyword">keyword</a>.
  </td>
</tr>
<tr id="tt_auto_toplevel">
  <td>"auto_toplevel"</td>
  <td>
    The page was specified in the command line or is the start page.
  </td>
</tr>
<tr id="tt_form_submit">
  <td>"form_submit"</td>
  <td>
    The user filled out values in a form and submitted it.
    Note that in some situations &mdash;
    such as when a form uses script to submit contents &mdash;
    submitting a form does not result in this transition type.
  </td>
</tr>
<tr id="tt_reload">
  <td>"reload"</td>
  <td>
    The user reloaded the page,
    either by clicking the reload button
    or by pressing Enter in the address bar.
    Session restore and Reopen closed tab use this transition type, too.
  </td>
</tr>
<tr id="tt_keyword">
  <td>"keyword"</td>
  <td>
    The URL was generated from a replaceable keyword
    other than the default search provider.
    See also
    <a href="#tt_keyword_generated">keyword_generated</a>.
  </td>
</tr>
<tr id="tt_keyword_generated">
  <td>"keyword_generated"</td>
  <td>
    Corresponds to a visit generated for a keyword.
    See also <a href="#tt_keyword">keyword</a>.
  </td>
</tr>
</table>

<h2 id="examples">Examples</h2>

<p>
For examples of using this API, see the
<a href="http://src.chromium.org/viewvc/chrome/trunk/src/chrome/common/extensions/docs/examples/api/history/">history sample directory</a> and the
<a href="http://src.chromium.org/viewvc/chrome/trunk/src/chrome/test/data/extensions/api_test/history/">history API test directory</a>.
For other examples and for help in viewing the source code, see
<a href="samples.html">Samples</a>.
</p>