How can I use jQuery in Greasemonkey scripts in Google Chrome?

StackOverflow https://stackoverflow.com/questions/2246901

Question

As some of you may know, Google Chrome has put some severe limitation on Greasemonkey scripts.

Chromium does not support @require, @resource, unsafeWindow, GM_registerMenuCommand, GM_setValue, or GM_getValue.

Without require, I can't find a way to include the jQuery library in Greasemonkey script under Google Chrome.

Does anybody have some advice in this matter?

Was it helpful?

Solution

From "User Script Tip: Using jQuery - Erik Vold's Blog"

// ==UserScript==
// @name         jQuery For Chrome (A Cross Browser Example)
// @namespace    jQueryForChromeExample
// @include      *
// @author       Erik Vergobbi Vold & Tyler G. Hicks-Wright
// @description  This userscript is meant to be an example on how to use jQuery in a userscript on Google Chrome.
// ==/UserScript==

// a function that loads jQuery and calls a callback function when jQuery has finished loading
function addJQuery(callback) {
  var script = document.createElement("script");
  script.setAttribute("src", "//ajax.googleapis.com/ajax/libs/jquery/1/jquery.min.js");
  script.addEventListener('load', function() {
    var script = document.createElement("script");
    script.textContent = "window.jQ=jQuery.noConflict(true);(" + callback.toString() + ")();";
    document.body.appendChild(script);
  }, false);
  document.body.appendChild(script);
}

// the guts of this userscript
function main() {
  // Note, jQ replaces $ to avoid conflicts.
  alert("There are " + jQ('a').length + " links on this page.");
}

// load jQuery and execute the main function
addJQuery(main);

OTHER TIPS

I have written a few functions based on the Erik Vold's script to help run me run functions, code and other scripts in a document. You can use them to load jQuery into the page and then run code under the global window scope.

Example Usage

// ==UserScript==
// @name           Example from http://stackoverflow.com/q/6834930
// @version        1.3
// @namespace      http://stackoverflow.com/q/6834930
// @description    An example, adding a border to a post on Stack Overflow.
// @include        http://stackoverflow.com/questions/2246901/*
// ==/UserScript==

var load,execute,loadAndExecute;load=function(a,b,c){var d;d=document.createElement("script"),d.setAttribute("src",a),b!=null&&d.addEventListener("load",b),c!=null&&d.addEventListener("error",c),document.body.appendChild(d);return d},execute=function(a){var b,c;typeof a=="function"?b="("+a+")();":b=a,c=document.createElement("script"),c.textContent=b,document.body.appendChild(c);return c},loadAndExecute=function(a,b){return load(a,function(){return execute(b)})};

loadAndExecute("//ajax.googleapis.com/ajax/libs/jquery/1.6.2/jquery.min.js", function() {
    $("#answer-6834930").css("border", ".5em solid black");
});

You can click here to install it, if you trust that I'm not trying to trick you into installing something malicious and that nobody has edited my post to point to something else. Reload the page and you should see a border around my post.

Functions

load(url, onLoad, onError)

Loads the script at url into the document. Optionally, callbacks may be provided for onLoad and onError.

execute(functionOrCode)

Inserts a function or string of code into the document and executes it. The functions are converted to source code before being inserted, so they lose their current scope/closures and are run underneath the global window scope.

loadAndExecute(url, functionOrCode)

A shortcut; this loads a script from url, then inserts and executes functionOrCode if successful.

Code

function load(url, onLoad, onError) {
    e = document.createElement("script");
    e.setAttribute("src", url);

    if (onLoad != null) { e.addEventListener("load", onLoad); }
    if (onError != null) { e.addEventListener("error", onError); }

    document.body.appendChild(e);

    return e;
}

function execute(functionOrCode) {
    if (typeof functionOrCode === "function") {
        code = "(" + functionOrCode + ")();";
    } else {
        code = functionOrCode;
    }

    e = document.createElement("script");
    e.textContent = code;

    document.body.appendChild(e);

    return e;
}

function loadAndExecute(url, functionOrCode) {
    load(url, function() { execute(functionOrCode); });
}

Use jQuery without fear of conflicts, by calling jQuery.noConflict(true). Like so:

function GM_main ($) {
    alert ('jQuery is installed with no conflicts! The version is: ' + $.fn.jquery);
}

add_jQuery (GM_main, "1.7.2");

function add_jQuery (callbackFn, jqVersion) {
    jqVersion       = jqVersion || "1.7.2";
    var D           = document;
    var targ        = D.getElementsByTagName ('head')[0] || D.body || D.documentElement;
    var scriptNode  = D.createElement ('script');
    scriptNode.src  = 'http://ajax.googleapis.com/ajax/libs/jquery/'
                    + jqVersion
                    + '/jquery.min.js'
                    ;
    scriptNode.addEventListener ("load", function () {
        var scriptNode          = D.createElement ("script");
        scriptNode.textContent  =
            'var gm_jQuery  = jQuery.noConflict (true);\n'
            + '(' + callbackFn.toString () + ')(gm_jQuery);'
        ;
        targ.appendChild (scriptNode);
    }, false);
    targ.appendChild (scriptNode);
}

But, For cross-browser scripts, why not take advantage of a nice, fast, local copy of jQuery, when you can?

The following works as a Chrome userscript and a Greasemonkey script, and it uses the nice local @require copy of jQuery, if the platform supports it.

// ==UserScript==
// @name     _Smart, cross-browser jquery-using script
// @include  http://YOUR_SERVER.COM/YOUR_PATH/*
// @require  http://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js
// @grant    GM_info
// ==/UserScript==

function GM_main ($) {
    alert ('jQuery is installed with no conflicts! The version is: ' + $.fn.jquery);
}

if (typeof jQuery === "function") {
    console.log ("Running with local copy of jQuery!");
    GM_main (jQuery);
}
else {
    console.log ("fetching jQuery from some 3rd-party server.");
    add_jQuery (GM_main, "1.7.2");
}

function add_jQuery (callbackFn, jqVersion) {
    var jqVersion   = jqVersion || "1.7.2";
    var D           = document;
    var targ        = D.getElementsByTagName ('head')[0] || D.body || D.documentElement;
    var scriptNode  = D.createElement ('script');
    scriptNode.src  = 'http://ajax.googleapis.com/ajax/libs/jquery/'
                    + jqVersion
                    + '/jquery.min.js'
                    ;
    scriptNode.addEventListener ("load", function () {
        var scriptNode          = D.createElement ("script");
        scriptNode.textContent  =
            'var gm_jQuery  = jQuery.noConflict (true);\n'
            + '(' + callbackFn.toString () + ')(gm_jQuery);'
        ;
        targ.appendChild (scriptNode);
    }, false);
    targ.appendChild (scriptNode);
}

If the page already has jQuery, then just follow this template:

// ==UserScript==
// @name          My Script
// @namespace     my-script
// @description   Blah
// @version       1.0
// @include       http://site.com/*
// @author        Me
// ==/UserScript==

var main = function () {

    // use $ or jQuery here, however the page is using it

};

// Inject our main script
var script = document.createElement('script');
script.type = "text/javascript";
script.textContent = '(' + main.toString() + ')();';
document.body.appendChild(script);

The simple way is using required keyword:

// @require     http://code.jquery.com/jquery-latest.js

There's a really easy way to get around including a full copy of jQuery for Chrome scripts when those scripts don't actually use any privileged features (GM_* functions, etc)...

Simply insert the script itself into the page DOM and execute! The best part is that this technique works just as well on Firefox+Greasemonkey, so you can use the same script for both: 

var script = document.createElement("script");
script.type = "text/javascript";
script.textContent = "(" + threadComments.toString() + ")(jQuery)";
document.body.appendChild(script);

function threadComments($) {
    // taken from kip's http://userscripts-mirror.org/scripts/review/62163
    var goodletters = Array('\u00c0','\u00c1','\u00c2','\u00c3','\u00c4','\u00c5','\u00c6','\u00c7'
                             ,'\u00c8','\u00c9','\u00ca','\u00cb','\u00cc','\u00cd','\u00ce','\u00cf'
                                      ,'\u00d1','\u00d2','\u00d3','\u00d4','\u00d5','\u00d6'         
                             ,'\u00d8','\u00d9','\u00da','\u00db','\u00dc','\u00dd'                  
                             ,'\u00e0','\u00e1','\u00e2','\u00e3','\u00e4','\u00e5','\u00e6','\u00e7'
                             ,'\u00e8','\u00e9','\u00ea','\u00eb','\u00ec','\u00ed','\u00ee','\u00ef'
                                      ,'\u00f1','\u00f2','\u00f3','\u00f4','\u00f5','\u00f6'         
                             ,'\u00f8','\u00f9','\u00fa','\u00fb','\u00fc','\u00fd'         ,'\u00ff').join('');

    // from Benjamin Dumke's http://userscripts-mirror.org/scripts/review/68252
    function goodify(s)
      {
         good = new RegExp("^[" + goodletters + "\\w]{3}");
         bad = new RegExp("[^" + goodletters + "\\w]");
         original = s;
         while (s.length >3 && !s.match(good)) {
            s = s.replace(bad, "");
            }
         if (!s.match(good))
         {
           // failed, so we might as well use the original
           s = original;
         }
         return s;
      }  

    in_reply_to = {};


    function who(c, other_way) {


        if (other_way)
        {
            // this is closer to the real @-reply heuristics
            m = /@(\S+)/.exec(c);
        }
        else
        {
            m = /@([^ .:!?,()[\]{}]+)/.exec(c);
        }
        if (!m) {return}
        if (other_way) {return goodify(m[1]).toLowerCase().slice(0,3);}
        else {return m[1].toLowerCase().slice(0,3);}
    }

    function matcher(user, other_way) {
        if (other_way)
        {
            return function () {
                return goodify($(this).find(".comment-user").text()).toLowerCase().slice(0,3) == user
                }
        }
        else
        {
            return function () {
                return $(this).find(".comment-user").text().toLowerCase().slice(0,3) == user
                }
        }
    }

    function replyfilter(id) {
        return function() {
            return in_reply_to[$(this).attr("id")] == id;
        }
    }

    function find_reference() {
        comment_text = $(this).find(".comment-text").text();
        if (who(comment_text))
        {
            fil = matcher(who(comment_text));
            all = $(this).prevAll("tr.comment").filter(fil);
            if (all.length == 0)
            {
                // no name matched, let's try harder
                fil = matcher(who(comment_text, true), true);
                all = $(this).prevAll("tr.comment").filter(fil);
                if (all.length == 0) {return}
            }
            reference_id = all.eq(0).attr("id");
            in_reply_to[$(this).attr("id")] = reference_id;
        }
    }


    // How far may comments be indented?
    // Note that MAX_NESTING = 3 means there are
    // up to *four* levels (including top-level)
    MAX_NESTING = 3

    // How many pixels of indentation per level?
    INDENT = 30

    function indenter(parent) {

        for (var i = MAX_NESTING; i > 0; i--)
        {
            if (parent.hasClass("threading-" + (i-1)) || (i == MAX_NESTING && parent.hasClass("threading-" + i)))
            {
                return function() {
                    $(this).addClass("threading-" + i).find(".comment-text").css({"padding-left": INDENT*i});
                }
            }
        }

        return function() {
            $(this).addClass("threading-1").find(".comment-text").css({"padding-left": INDENT});
        }

    }

    function do_threading(){
        id = $(this).attr("id");
        replies = $(this).nextAll("tr.comment").filter(replyfilter(id));
        ind = indenter($(this));
        replies.each(ind);
        replies.insertAfter(this);
    }

    function go() {
        $("tr.comment").each(find_reference);
        $("tr.comment").each(do_threading);
    }

    $.ajaxSetup({complete: go});
    go();
}

(unapologetically stolen from Shog9 on meta.stackoverflow since he didn't move it here, and I have to delete the meta post..)

Also, you could pack your script with jQuery to Chrome extension. See Google Chrome's Content Scripts.

Chrome extensions, unlike Greasemonkey scripts, can auto-update itself.

Easier solution: cut+paste the contents of jquery.min.js into the top of your user script. Done.

I found various problems with the recommended answers. The addJQuery() solution works on most pages but has bugs on many. If you run into issues just copy+paste the jquery contents into your script.

I wonder if you couldn't rely on document.defaultView.jQuery in your GM script ala:

if (document.defaultView.jQuery) {
  jQueryLoaded(document.defaultView.jQuery);
} else {
  var jq = document.createElement('script');
  jq.src = 'http://jquery.com/src/jquery-latest.js';
  jq.type = 'text/javascript';
  document.getElementsByTagName('head')[0].appendChild(jq);
  (function() { 
    if (document.defaultView.jQuery) jQueryLoaded(document.defaultView.jQuery);
    else setTimeout(arguments.callee, 100);
  })();
}

function jQueryLoaded($) {
  console.dir($);
}

Another approach would be to modify your script to load jQuery manually. Example from http://joanpiedra.com/jquery/greasemonkey/:

// Add jQuery
var GM_JQ = document.createElement('script');
GM_JQ.src = 'http://jquery.com/src/jquery-latest.js';
GM_JQ.type = 'text/javascript';
document.getElementsByTagName('head')[0].appendChild(GM_JQ);

// Check if jQuery's loaded
function GM_wait() {
    if(typeof unsafeWindow.jQuery == 'undefined') { window.setTimeout(GM_wait,100); }
else { $ = unsafeWindow.jQuery; letsJQuery(); }
}
GM_wait();

// All your GM code must be inside this function
function letsJQuery() {
    alert($); // check if the dollar (jquery) function works
}

EDIT: DRATS! After testing it appears this code does not work since Google Chrome runs userscripts/extensions in a separate scope/process from the actual webpage. You can download the jQuery code using an XmlhttpRequest and then Eval it, but you have to host the code on a server that allows Cross-Origin Resource Sharing using the Access-Control-Allow-Origin: * header. Sadly NONE of the current CDNs with jQuery support this.

Perfect extension to embed jQuery into Chrome Console as simple as you can imagine. This extension also indocates if jQuery has been already embeded into page.

This extension used to embed jQuery into any page you want. It allows to use jQuery in the console shell (You can invoke Chrome console by "Ctrl+Shift+j").

To embed jQuery into selected tab click on extention button.

LINK to extension: https://chrome.google.com/extensions/detail/gbmifchmngifmadobkcpijhhldeeelkc

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