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#REDIRECT [[Wikipedia:User scripts/Guide]]
[[Ajax (programming)|AJAX]] (''asynchronous JavaScript and XML'') is a popular name for a web programming technique that queries the server or fetches content without reloading the entire page.
While programming AJAX can be complex, libraries of functions can make it much easier. Since the [[mw:MediaWiki 1.16|1.16 release]], MediaWiki comes with the [[jQuery]] library, which provides a convenient framework for easily making Ajax requests. Prior to version 1.17, MediaWiki provided [{{SERVER}}/w/skins-1.5/common/ajax.js ajax.js], containing a small set of functions by default. User scripts such as [[m:User:Pathoschild/Scripts/Ajax framework|Pathoschild's AJAX framework]] also provided a more comprehensive library of functions, but is now obsolete. The examples using these old methods are kept for historical reasons.
==Common problems==
* <p>AJAX programmers commonly run into problems if they don't account for AJAX's ''asynchronicity''. If you try to pop up a box with another page's content, you will almost certainly pop up a box containing <code>'''null'''</code>. This occurs because the script continued even though the query wasn't finished.</p><!--
--><p>To correct the problem, you need to use [[w:callback (computer science)|callback functions]]. Place the next portion of code after a query into a function, and call the function when the query completes. jQuery makes this very easy to do.</p>
* AJAX scripts cannot reach a page on a different server (for example, ''google.ca'' or ''en.wikisource.org'' from ''en.wikipedia.org''). Trying to do so will cause the script to halt with or without error. This can be circumvented using a proxy on the current server, but none is available for Wikimedia user scripts.
== Basic examples ==
MediaWiki provides some modules with helper funtions which facilitate the use of its API. The main modules available are
* [https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/resources/mediawiki.api/mediawiki.api.js?view=markup mediawiki.api]
* [https://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/resources/mediawiki.api/mediawiki.api.edit.js?view=markup mediawiki.api.edit]
If your script makes use any method or code provided by these modules, remember to indicate the dependencies with [[mw:ResourceLoader/Default_modules#mediaWiki.loader|mw.loader.using]] or, in case of gadgets, on its definition at [[MediaWiki:Gadgets-definition]].
=== Fetch page content ===
Fetching a page content can be done using [[GET]].
<source lang="javascript">
$.ajax({
url: mw.util.wikiGetlink( 'Wikipedia:Sandbox' ),
success: function( data ) {
alert( 'The remote page contains:\n' + data );
},
error: function() {
alert( 'The ajax request failed.' );
}
});
</source>
=== Get the wikicode of a page ===
<source lang="javascript">
var api = new mw.Api();
api.get( {
action: 'query',
prop: 'revisions',
rvprop: 'content',
rvlimit: 1,
indexpageids: true,
titles: 'Wikipedia:Sandbox'
}, {
ok: function ( data ) {
var q = data.query,
id = q && q.pageids && q.pageids[0],
pg = id && q.pages && q.pages[ id ],
rv = pg && pg.revisions;
if ( rv && rv[0] && rv[0]['*'] ) {
alert( 'The wikicode of the page "' + pg.title + '" is:\n\n' + rv[0]['*'] );
}
}
} );
</source>
===Edit a page and other common actions===
Scripts can perform common actions (like editing, protection, blocking, deletion, etc.) through the [{{SERVER}}/w/api.php API]. These actions require an edit token, which is valid for any action during the same session. (However, you should get a new token for different tasks in case this changes in the future.)
The code below shows how to edit a page, but it can easily be adapted to other actions by reading the [{{SERVER}}/w/api.php API documentation].
<source lang="javascript">
// Edit page (must be done through POST)
function editPage( info ) {
$.ajax({
url: mw.util.wikiScript( 'api' ),
type: 'POST',
dataType: 'json',
data: {
format: 'json',
action: 'edit',
title: info.title,
text: info.text,
summary: info.summary,
token: mw.user.tokens.get( 'editToken' )
},
success: function( data ) {
if ( data && data.edit && data.edit.result && data.edit.result == 'Success' ) {
alert( 'Page edited!' );
} else {
alert( 'The edit query returned an error. =(' );
}
},
error: function() {
alert( 'The ajax request failed.' );
}
});
}
editPage({
title: 'User:' + mw.config.get( 'wgUserName' ) + '/Sandbox',
text: 'Cool! It works! :-) ~~' + '~~',
summary: 'Trying to edit my sandbox [[Project:WikiProject User scripts/Guide/Ajax|using AJAX]]...'
});
</source>
==Deprecated methods ==
===Create an AJAX object===
==== MediaWiki ajax.js ====
Before you can query or fetch a page, you must create a query object. Different browsers use different objects, but MediaWiki provides the <code>sajax_init_object()</code> to do it in one step. The [[m:User:Pathoschild/Scripts/Ajax framework|AJAX framework]] equivalent is <code>ajax_create()</code> (see [[#AJAX framework|section below]]).
<source lang="javascript">
var query = sajax_init_object();
</source>
==== AJAX framework ====
<source lang="javascript">
var query = ajax_create();
</source>
===Fetch page content===
Fetching a page content can be done using [[GET]].
==== MediaWiki ajax.js ====
<source lang="javascript">
// fetch
var api = sajax_init_object();
api.open('GET', 'http://example.com', true);
api.onreadystatechange = show_result;
api.send(null);
// handle response
function show_result(_api) {
if(_api.readyState==4) {
if(_api.status==200) {
alert('The remote page contains:\n' + _api.responseText);
} else {
alert('The query returned an error.');
}
}
}
</source>
==== AJAX framework ====
<source lang="javascript">
ajax_get('http://example.com', show_result);
function show_result(_api) {
if(_api.ajax_success) {
alert('The remote page contains:\n' + _api.responseText);
} else {
alert('An error occurred.');
}
}
</source>
===Edit a page and other common actions===
==== MediaWiki ajax.js ====
<source lang="javascript">
// fetch token
var api = sajax_init_object();
api.open('GET', wgServer + wgScriptPath + '/api.php?format=json&action=query&prop=info&indexpageids=1&intoken=edit&titles=Whatever', true);
api.onreadystatechange = extract_token;
api.send(null);
function extract_token() {
if(api.readyState==4) {
if(api.status==200) {
var response = eval('(' + api.responseText + ')');
var token = response['query']['pages'][response['query']['pageids'][0]]['edittoken'];
edit_page(token);
}
else {
alert('The token query returned an error.');
}
}
}
// edit page (must be done through POST)
function edit_page(_token) {
var parameters = 'action=edit&title=User:Pathoschild/Sandbox&text=AJAX_test!&token=' + encodeURIComponent(_token);
api.open('POST', wgServer + wgScriptPath + '/api.php', true); // just reuse the same query object
api.onreadystatechange = alert_result;
api.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
api.setRequestHeader('Connection', 'keep-alive');
api.setRequestHeader('Content-length', parameters.length);
api.send(parameters);
// process response
function alert_result() {
if(api.readyState==4) {
if(api.status==200) {
alert('Page edited!');
}
else {
alert('The query returned an error.');
}
}
}
}
</source>
==== AJAX framework ====
<source lang="javascript">
ajax_edit_token('edit', edit_page);
function edit_page(_token) {
var parameters = 'action=edit&title=User:Pathoschild/Sandbox&text=AJAX_test!&token=' + encodeURIComponent(_token);
ajax_post(wgServer + wgScriptPath + '/api.php', parameters, alert_result);
}
function alert_result(_api) {
if(_api.ajax_success) {
alert('Page edited!');
} else {
alert('An error occurred.');
}
}
</source>
==Data sources==
===[{{SERVER}}{{SCRIPTPATH}}/api.php api.php]===
See [[mw:API]]. Usually used with [[JSON]] format.
===HTML===
You could fetch the whole article page or use <code>&action=render</code> URL parameter to get the content without all the menus ([{{fullurl:{{FULLPAGENAME}}|action=render}} example]). Also see [[mw:Manual:Parameters to index.php|Parameters to index.php]].
The result you could treat as a text but it's usually convenient to parse it as HTML document, e.g. using DOMParser object <small>(examples needed)</small>.
===Wiki code===
To get the wiki code you use <code>&action=raw</code> URL parameter ([{{fullurl:{{FULLPAGENAME}}|action=raw}} example]).
The result you treat as a text.
===Preview===
Sometimes you might want to use preview. For example, [[Special:Prefixindex]] won't work with <code>&action=render</code>. To get rid of the unnecessary menus you could submit <tt><nowiki>{{Special:Prefixindex/somepage}}</nowiki></tt> for a preview and get a "clean" list (nevertheless, it's better to use API for prefix index)
==See also==
* [[mw:ResourceLoader/JavaScript Deprecations#ajax.js]]
* [[mw:ResourceLoader/Default modules#jQuery & plugins]]
===Code===
;User scripts
:* [[m:User:Pathoschild/Scripts/Ajax framework|Comprehensive AJAX framework]] (by [[user:Pathoschild|Pathoschild]])
:* [[User:TheFearow/simpleajax.js|AJAX editing]] (by [[user:TheFearow|TheFearow]])
:* [[User talk:Alex Smotrov/qpreview.js|Ajax preview]] (by [[user:Alex Smotrov|Alex Smotrov]])
:* [[User talk:Alex Smotrov/wlunwatch.js|Ajax unwatch from watchlist]] (by [[user:Alex Smotrov|Alex Smotrov]])
:* Various code with AJAX
:** [[Wikipedia:Tools/Navigation popups|Navigation popups]]
:** [[Wikipedia:WikiProject User scripts/Scripts/Twinkle|Twinkle]] (some code in [[User:AzaToth/morebits.js]], and good examples of AJAX are in the bottom of [[User:AzaToth/twinklespeedy.js]])
:** [[User:Kaldari/wikilove.js]] - uses Ajax (via jQuery) to edit user talk pages
; Mediawiki
:* [{{SERVER}}/w/skins-1.5/common/ajax.js ajax.js] - some support functions
:* [{{SERVER}}/w/skins-1.5/common/ajaxwatch.js ajaxwatch.js] - watch/unwatch
:* [{{SERVER}}/w/skins-1.5/common/upload.js upload.js] - licenses preview on [[Special:Upload]]
:* Internal and disabled code
:** [http://svn.wikimedia.org/viewvc/mediawiki/trunk/phase3/includes/AjaxFunctions.php?view=markup AjaxFunctions.php] has 2 main functions:
:**: wfAjaxWatch - server part of ajaxwatch.js
:**: wfSajaxSearch - disabled on WMF projects. If it was enabled, [{{SERVER}}/w/skins-1.5/common/ajaxsearch.js ajaxsearch.js] would be responsible for the client side. Also see [[mw:Manual:$wgAjaxSearch]].
:** [[mw:Manual:Live preview|Live preview]] ([{{SERVER}}/w/skins-1.5/common/preview.js preview.js])
===Alternatives===
* [[IFrame]]s are an obsolete older method (see [[User:TheFearow/ajax.js|a small untested library]] by [[user:TheFearow|TheFearow]])
* URL parameters: a script can call itself on a different by adding a custom URL parameter to the address bar. It can then check the address bar on every page load, and run code depending on the values of the custom headers. See [[User:Lupin/autoedit.js|an example unmaintaned library]] by [[user:Lupin|Lupin]]).
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