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

Question

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

Chromium does not support @require,

Answer 1

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);

Answer 2

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

Answer 3

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..)

Answer 4

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

Answer 5

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);

Answer 6

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.