There a few similar questions, but none of them have really gotten at what I'm asking.
I have a browser action popup. In the popup, I want to display settings if you're on a page where the content script has been injected (i.e., any page that matches the matches key within the content_scripts in the `manifest).
If I'm on a page that doesn't match the content_scripts matches pattern (and so wasn't injected), I just want to display a generic message "this plugin activates when you're on so-and-so sites".
What is the cleanest way to do it, without adding any unnecessary permissions?
It seems like one option is sending a message to a content script in the active tab, and seeing if I get a reply, but that seems really.. hacky. I should be able to know just based on a regex if I'm on one of the domains that matches my content script.
I'm looking for something that works in both manifest v2 and v3, btw.
TL;DR;
What's the simplest way to display a "you're on a page that matches your content_script" or "you're not on a page that matches your content_script" in a browser_action popup?
I build chrome extensions full time for an agency and have had projects where I needed to do exactly what you're asking.
The solution can be implemented w/o any permissions whatsoever. I built mine locally with an empty array for permissions. (for mv3)
for popup.html just create 2 divs and have them default to display none.
<div id="unsupported" style="display: none;">Ooops! This is not a supported site.</div>
<div id="supported" style="display: none;">Wohoo! This is a supported site!!!!!</div>
for your script.js, wait till the popup loads then query the active tab in the current window and get that tab's ID to send a message directly to it. If the tab is supported with a content script, it will send a true response (see last code snippet). If it wasn't supported, it will be an 'undefined' response.
async function setUI() {
let tabData = await chrome.tabs.query({ active: true, currentWindow: true })
let tabId = tabData[0].id // tabs.query returns an array, but we filtered to active tab within current window which yields only 1 object in the array
chrome.tabs.sendMessage(tabId, {
'message': 'isSupported'
}, (response) => {
console.log(response)
// response will be true if the message was successfuly sent to the tab and "undefined" if the message was never received (i.e. not supported w/ your content script)
if (response) return showSupportedHTML()
// else
showUnsupportedHTML()
})
}
function showSupportedHTML() {
document.querySelector('#supported').style['display'] = ''
}
function showUnsupportedHTML() {
document.querySelector('#unsupported').style['display'] = ''
}
window.addEventListener('DOMContentLoaded', () => {
setUI()
})
Lastly, in your content script, add a message listener to receive the message 'isSupported' that comes in from your content script. If the content script receives that message, have it send a response back with 'true'.
chrome.runtime.onMessage.addListener(function (request, sender, sendResponse) {
if (request.message == 'isSupported') {
console.log('run')
sendResponse(true)
}
})
Now, this of course only works for manifest v3 because as far as I know you can't use chrome.tabs.query for mv2. However, I recommend this solution as I've implemented pretty much this exact same code in other projects for clients and it's never had any issues.
I could look into a solution for mv2, though using the "activeTab" permission would be the right way to do it, I believe. Now, if you really don't want to go that route then you could implement a rather hacky solution. For example, you could use window 'focus' and window 'blur' events to see when a user has entered or left a tab. Then set a local storage variable every time a user enters / leaves a supported page. The order of operations for blur and focus is always blur => focus. So, when the blur event occurs you set a local storage variable to false. However, if you leave a supported tab for another supported tab then the 'focus' event will trigger immediately afterwards so you can set that same storage variable back to true.
Now, your content script will load after the tab has been focused so you'll need to add a function for when the page loads. You can run something like document.hidden and if that returns true, do nothing because the user already left this tab. If it returns false, then the user is still on the tab and you can set your local storage variable to true.
When the user opens the popup, you'll check that local storage variable and if its true or false, you can set the UI accordingly.
Let me know if the mv2 solution made sense or sounds too hacky. Happy to look into it more! :)
edit: Here is the code for mv2, I tested it and it does work and without any permissions, other than storage which is not an invasive permission.
Script.js for the mv2 popup:
async function setUI() {
chrome.storage.local.get(['isSupported'], function (response) {
console.log(response['isSupported'])
// response will be true if the message was successfuly sent to the tab and "undefined" if the message was never received (i.e. not supported w/ your content script)
if (response['isSupported']) return showSupportedHTML()
// else
showUnsupportedHTML()
})
}
function showSupportedHTML() {
document.querySelector('#supported').style['display'] = ''
}
function showUnsupportedHTML() {
document.querySelector('#unsupported').style['display'] = ''
}
window.addEventListener('DOMContentLoaded', () => {
setUI()
})
code for the content script in mv2:
if (!document.hidden) chrome.storage.local.set({'isSupported': true})
window.addEventListener('blur', () => {
console.log('left site')
chrome.storage.local.set({'isSupported': false})
})
window.addEventListener('focus', () => {
console.log('entered site')
chrome.storage.local.set({'isSupported': true})
})
Let me know if you have any additional questions.
Disclaimer: I have no prior browser extension development experience and am just going by the docs. I might be spouting nonsense or giving an answer that is plainly against your requirements, but that would be out of ignorance and not malicious intent. If you find my answer problematic, comment, or cast a vote and move on.
According to MDN, the activeTab permission allows to read the active tab's Tab.url property. One solution could be to request that permission, and then use that API to get the active tab's URL, and then use the same regex from the manifest.json's matches property to test for a match, and then use that information to modify your extension's browser_action UI.
You should be able to read the matches property from the manifest file via the .runtime.getManifest() API. MDN docs, chrome docs.
Snippet to get active tab in a background script: tabs.query({active: true}). (link to MDN docs). A content script should instead use tabs.getCurrent and the Tab.active property of the resolved result.
If you don't want to request the activeTab permission, what you're suggesting with the message-passing between the browser_action scripts and the content scripts might be the right way to go, but I don't know for a fact. The tabs.onActivated event would probably be useful with this approach. Note that to send a message from a background script to a content script, you need to use tabs.sendMessage (MDN docs, chrome docs) instead of runtime.sendMessage.
Another possible (maybe?) approach would be to listen for the tab change in the content script and then send the notification message from the content script to the extension's background scripts via the onfocus event (or similar events), and runtime.sendMessage.
If you go with a messaging-related approach, you might want to put a condition in the content script to only do messaging if the content script is in the top frame of the tab (Ie. iframes don't do messaging), since only one frame of the tab really needs to do this kind of messaging when the active tab changes, and content scripts can be applied to all frames in a browsing context.
Of these possible solutions I can think of, I don't know which is best for you, since you want both minimal permission requirements and a simple/clean approach, and each seems to be a tradeoff.
Related
Essentially I want to have a script execute when the contents of a DIV change. Since the scripts are separate (content script in the Chrome extension & webpage script), I need a way simply observe changes in DOM state. I could set up polling but that seems sloppy.
For a long time, DOM3 mutation events were the best available solution, but they have been deprecated for performance reasons. DOM4 Mutation Observers are the replacement for deprecated DOM3 mutation events. They are currently implemented in modern browsers as MutationObserver (or as the vendor-prefixed WebKitMutationObserver in old versions of Chrome):
MutationObserver = window.MutationObserver || window.WebKitMutationObserver;
var observer = new MutationObserver(function(mutations, observer) {
// fired when a mutation occurs
console.log(mutations, observer);
// ...
});
// define what element should be observed by the observer
// and what types of mutations trigger the callback
observer.observe(document, {
subtree: true,
attributes: true
//...
});
This example listens for DOM changes on document and its entire subtree, and it will fire on changes to element attributes as well as structural changes. The draft spec has a full list of valid mutation listener properties:
childList
Set to true if mutations to target's children are to be observed.
attributes
Set to true if mutations to target's attributes are to be observed.
characterData
Set to true if mutations to target's data are to be observed.
subtree
Set to true if mutations to not just target, but also target's descendants are to be observed.
attributeOldValue
Set to true if attributes is set to true and target's attribute value before the mutation needs to be recorded.
characterDataOldValue
Set to true if characterData is set to true and target's data before the mutation needs to be recorded.
attributeFilter
Set to a list of attribute local names (without namespace) if not all attribute mutations need to be observed.
(This list is current as of April 2014; you may check the specification for any changes.)
Edit
This answer is now deprecated. See the answer by apsillers.
Since this is for a Chrome extension, you might as well use the standard DOM event - DOMSubtreeModified. See the support for this event across browsers. It has been supported in Chrome since 1.0.
$("#someDiv").bind("DOMSubtreeModified", function() {
alert("tree changed");
});
See a working example here.
Many sites use AJAX/XHR/fetch to add, show, modify content dynamically and window.history API instead of in-site navigation so current URL is changed programmatically. Such sites are called SPA, short for Single Page Application.
Usual JS methods of detecting page changes
MutationObserver (docs) to literally detect DOM changes.
Info/examples:
How to change the HTML content as it's loading on the page
Performance of MutationObserver to detect nodes in entire DOM.
Lightweight observer to react to a change only if URL also changed:
let lastUrl = location.href;
new MutationObserver(() => {
const url = location.href;
if (url !== lastUrl) {
lastUrl = url;
onUrlChange();
}
}).observe(document, {subtree: true, childList: true});
function onUrlChange() {
console.log('URL changed!', location.href);
}
Event listener for sites that signal content change by sending a DOM event:
pjax:end on document used by many pjax-based sites e.g. GitHub,
see How to run jQuery before and after a pjax load?
message on window used by e.g. Google search in Chrome browser,
see Chrome extension detect Google search refresh
yt-navigate-finish used by Youtube,
see How to detect page navigation on YouTube and modify its appearance seamlessly?
Periodic checking of DOM via setInterval:
Obviously this will work only in cases when you wait for a specific element identified by its id/selector to appear, and it won't let you universally detect new dynamically added content unless you invent some kind of fingerprinting the existing contents.
Cloaking History API:
let _pushState = History.prototype.pushState;
History.prototype.pushState = function (state, title, url) {
_pushState.call(this, state, title, url);
console.log('URL changed', url)
};
Listening to hashchange, popstate events:
window.addEventListener('hashchange', e => {
console.log('URL hash changed', e);
doSomething();
});
window.addEventListener('popstate', e => {
console.log('State changed', e);
doSomething();
});
P.S. All these methods can be used in a WebExtension's content script. It's because the case we're looking at is where the URL was changed via history.pushState or replaceState so the page itself remained the same with the same content script environment.
Another approach depending on how you are changing the div.
If you are using JQuery to change a div's contents with its html() method, you can extend that method and call a registration function each time you put html into a div.
(function( $, oldHtmlMethod ){
// Override the core html method in the jQuery object.
$.fn.html = function(){
// Execute the original HTML method using the
// augmented arguments collection.
var results = oldHtmlMethod.apply( this, arguments );
com.invisibility.elements.findAndRegisterElements(this);
return results;
};
})( jQuery, jQuery.fn.html );
We just intercept the calls to html(), call a registration function with this, which in the context refers to the target element getting new content, then we pass on the call to the original jquery.html() function. Remember to return the results of the original html() method, because JQuery expects it for method chaining.
For more info on method overriding and extension, check out http://www.bennadel.com/blog/2009-Using-Self-Executing-Function-Arguments-To-Override-Core-jQuery-Methods.htm, which is where I cribbed the closure function. Also check out the plugins tutorial at JQuery's site.
In addition to the "raw" tools provided by MutationObserver API, there exist "convenience" libraries to work with DOM mutations.
Consider: MutationObserver represents each DOM change in terms of subtrees. So if you're, for instance, waiting for a certain element to be inserted, it may be deep inside the children of mutations.mutation[i].addedNodes[j].
Another problem is when your own code, in reaction to mutations, changes DOM - you often want to filter it out.
A good convenience library that solves such problems is mutation-summary (disclaimer: I'm not the author, just a satisfied user), which enables you to specify queries of what you're interested in, and get exactly that.
Basic usage example from the docs:
var observer = new MutationSummary({
callback: updateWidgets,
queries: [{
element: '[data-widget]'
}]
});
function updateWidgets(summaries) {
var widgetSummary = summaries[0];
widgetSummary.added.forEach(buildNewWidget);
widgetSummary.removed.forEach(cleanupExistingWidget);
}
I am trying to reset a form so that it appears to Drupal 8 that it hasn't been submitted. So far I have been unable to do this, as I cannot find any available methods (setSubmitted() hardcodes it to TRUE without a FALSE option). The reason is this isn't a full submit, but a submit of one field after which I would like the user to be redirected to another page that has another form, and I would like this secondary form to use the value obtained in the first step.
In the submit handler for the first part I use this to redirect:
$form_state->setRedirect('my.route', [], []);
And this works, but when the form reaches the second form (it seems) that the second form thinks it is a submission. As a result any submit buttons I add to the second form seem to make it auto-submit, and this breaks my user journey.
In the submit for the first part I have tried:
$form_state->setRebuild(TRUE);
$form_state = new FormState();
unset($form_state);
Tried the above in various configurations to no avail. They all prevent/ignore the setRedirect call that I make afterwards. The reason I want/need to do it this way is I want to preserve the POST method used.
Do you want to obtain something similar to what core search module does? It has simple SearchBlockForm that sends data to more complex SearchPageForm.
SearchBlockForm uses GET method (though you may use POST):
$form['#method'] = 'get';
and has no id and token fields:
function search_form_search_block_form_alter(&$form, FormStateInterface $form_state) {
$form['form_build_id']['#access'] = FALSE;
$form['form_token']['#access'] = FALSE;
$form['form_id']['#access'] = FALSE;
}
BTW, the last change allows you to avoid running submit callbacks.
Hope this helps.
I want to create an "extension" for a Jacada Interaction (to extend functionality), in my case to parse and assign the numerical part of serialNumber (a letter, followed by digits) to a numeric global ("system") variable, say serialNumeric. What I am lacking is the structure and syntax to make this work, including the way to reference interaction variables from within the extension.
Here is my failed attempt, with lines commented out to make it innocuous after failing; I think I removed "return page;" after crashing, whereupon it still crashed:
initExtensions("serialNumeric", function(app){
app.registerExtension("loaded", function(ctx, page) {
// Place your extension code here
//$('[data-refname="snum"]').val('serialNumber');
// snum = Number(substring(serialNumber,1))
});
});
Here is an example of one that works:
/**
* Description: Add swiping gestures to navigate the next/previous pages
*/
initExtensions("swipe", function(app) {
// Swipe gestures (mobile only)
app.registerExtension('pageRenderer', function(ctx, page) {
page.swipe(function(evt) {
(evt.swipestart.coords[0] - evt.swipestop.coords[0] > 0)
? app.nextButton.trigger('click')
: app.backButton.trigger('click')
});
return page;
});
});
After reading the comment below, I tried the following, unsuccessfully (the modified question variable is not written back to that variable). It rendered poorly in the comment section, so I am putting it here:
initExtensions("serialNumeric", function(app){
app.registerExtension("loaded", function(ctx, page) {
var sernum = new String($('[data-refname="enter"] input'));
var snumeric = new String(sernum.substr(1));
$('[data-refname="enter"] input').val(snumeric);
});
});
I would like to understand when this code will run: it seems logical that it would run when the variable is assigned. Thanks for any insight ~
In your case, you extend loaded event. You don't have to return the page from the extension like in your working example below.
The page argument contains the DOM of the page you have just loaded, the ctx argument contains the data of the page in JSON form. You can inspect the content of both arguments in the browser's inspection tools. I like Chrome. Press F12 on Windows or Shift+Ctrl+I on Mac.
The selector $('[data-refname="snum"] input') will get you the input field from the question with the name snum that you defined in the designer. You can then place the value in the input field with the value from the serialNumber variable.
$('[data-refname="snum"] input').val(serialNumber);
You can also read values in the same way.
You can't (at this point) access interaction variables in the extension, unless you place theses variables inside question fields.
Here is a simple example how to put your own value programmatically into a input field and cause it to read it into the model, so upon next it will be sent to the server. You are welcome to try more sophisticated selectors to accommodate for your own form.
initExtensions("sample", function(app){
app.registerExtension("loaded", function(ctx, page) {
// simple selector
var i = $('input');
// set new value
i.val('some new value');
// cause trigger so we can read into our model
i.trigger('change');
});
});
I have following piece of code in my fiddlerscript:
RulesString("Redirect Foo", true)
RulesStringValue(0, "to the latest version", "latest")
RulesStringValue(1, "to a particular version... (e.g. 1.2.3)", "%CUSTOM%")
public static var foo_redirect: String = null;
It renders as a submenu and clicking Redirect Foo to a particular version... opens a prompt box where you can type something.
Now, I want to validate that the user typed something following a regexp, and not a totally random string, and display a FiddlerObject.alert if he put something non-conformant.
How can I do the validation just after the user inputs the value, but before there's any redirection happening? (I don't want to defer it to OnBeforeRequest since it may display dozens of alerts there, one per each session - Foo is a folder with many JS files).
Fiddler does not offer a mechanism to validate the values of the %CUSTOM% token at the point of entry. If you want to do that, don't use RulesString, instead use FiddlerScript or an extension to add a menu of your own devising.
I've been looking for a script that combines the autoGrowInput with the JEditable but found none.
Use https://github.com/MartinF/jQuery.Autosize.Input initialized automatically via jEditable's event data:
jQuery(element).editable(save_fn, {
data: function(value,settings} {
var target = event.target;
window.setTimeout(function(){
jQuery(target).find('input').autosizeInput();
});
return value;
}
});
It's worth noting that this event (data) fires before the input element is actually created, hence the use of the timeout. There doesn't seem to be an event available at the present time for after the input has been created.
Actually I have created a plugin that does exactly that. You can check the demo and the documentation. I tried to make it very intuitive. It has ajax capabilities, using the RESTful philosophy. If you liked the animation effect on the autoGrowInput, it will be really easy to add it to the plugin just by changing the css file, using the transition property.
If I get people to like it, I may be able to improve and add more features to it. Hope it helps.