Google Chrome Extension documentation has some good information here:
http://code.google.com/chrome/extensions/tut_analytics.html
I put the analytics tracking code in my background.html file.
However I tried putting the _gaq.push call inside a script that runs on the page and got an error saying that the variable _gaq is not defined.
So I have to put onclick events in every element on the page I want to track and from there, call a function in background.html? Is there a better way to track events?
You can do this with chrome.extension.sendRequest in the content script and chrome.extension.onRequest.addListener in the background.html page. See here for more details: http://code.google.com/chrome/extensions/messaging.html. Also be sure your manifest.json is correct; I ran into problems when I had a hyphen character instead of an underscore.
Related
I have an old Chrome extension that I want to update for manifest version 2. I noticed I have an eval function call that I cannot get rid of. I'm trying to understand the new Chrome sandbox feature that lets me do an eval call inside of it. The question is: by loading a sandbox page in the background, can I pass it a string containing something to execute, then have it executing the script, outputting the result on the popup page?
At first I thought this was possible but looking at the examples apparently the script to be evaluated has to be already in the sandbox page.
Thanks
Are Content Scripts (http://code.google.com/chrome/extensions/content_scripts.html) injected into prerendered pages (document.webkitVisibilityState== 'prerender') ?
I’ve been reading https://developers.google.com/chrome/whitepapers/prerender and https://developers.google.com/chrome/whitepapers/pagevisibility, and am trying to figure out how Content Scripts work with page prerendering/prefetching.
Thanks
TheZ, tomdemuyt: I’m afraid you guys are missing the point. ‘run_at’ specifies whether the content script is injected before or after the DOM is constructed.
However, I am talking about document.webkitVisibilityState, which can be ‘prerender’ (when the page is in a background/invisible tab), ‘hidden’, or ‘visible’. Note that webkitVisibilityState can transition from ‘prerender’ to ‘hidden’ or ‘visible’, or back and forth between ‘hidden’ and ‘visible’, without any changes being made to the DOM. (In order to better understand this, read the articles linked in my original post.)
I think I’ve been able to determine that content scripts ARE injected into prerendered pages. Here’s the problem, however: let’s say my content script does something that should not occur on a prerendered page. For instance, it does pageview count, or adds animation, neither of which should begin until the user is actually viewing the page. So it seems that my content script should do something like what’s shown in the code examples on https://developers.google.com/chrome/whitepapers/pagevisibility - check document.webkitVisibilityState, and also listen to the ‘webkitvisibilitychange’ event, and only do pageview count/start the animation when document.webkitVisibilityState is, or has transitioned to, ‘visible’.
I may have just answered my own question, but I just wanted to make sure that I was on the right track.
Thanks
As TheZ mentioned, you should ues the run_at setting.
Link to docs : http://code.google.com/chrome/extensions/content_scripts.html#registration
I would like to check the html of an element of a
chrome.tabs.executeScript(tab_id,{code: 'sendRequestToBackground(document.getElementById('important_val').innerHTML); '},
function(){
});
I want to be able to get this value from my background script, I saw a lot of examples with chrome.extension.sendRequest and chrome.extension.onRequest.addListener because all the examples is for working from the extension popup.html to background script and vice-versa.
But I open a brand new tab, change the URL, and I want to get a value of a field that (which btw is generated via Javascript) belongs to this random tab.
Is it possible to do that?
Thanks!
If you want to inject your code to a random tab, do this:
Be sure to have permissions to "tabs" and "<all_urls>" in your manifest.json
Get all tabs using chrome.tabs.query
Pick random tab using Math.random()
Inject the code using chrome.tabs.executeScript
In the incjected code call chrome.extension.sendRequest
On the background page receive the message using chrome.extension.onRequest
I am writing a chrome extension that is a 'content script'
I want to inject a google map on to a webpage.
Problem:
It appears that i have no way to add functions on to the window object, thus i cannot define a callback function for googlemaps to call when it loads.
How do people usually go about mucking with the window?
--
someone on the interwebs suggested i do this:
You can do this easily with a JavaScript URL: window.location =
"javascript:obj.funcvar = function() {}; void(0);"
but when i did this i got an access denied error. it seems like a lot of search results about this problem are outdated.
Content scripts have a separate JavaScript execution ennvironment from the page they run on, so they cannot alter JS variables in the page itself. However, the content script shares the DOM with the page, so you can inject a <script> tag into the DOM which will be loaded and run in the actual page's execution environment.
I'm trying to build a chrome extension that overrides a download of a file and displays it in the browser. For example if you click on a link to a '.csv' file I'd like it to render in the browser instead of downloading it.
Chrome already does it for PDF's types and the Xml Tree extension also does exactly that for xml files.
So it should be possible, just not sure how to go about catching that event?
An implementation along the lines indicated by in the previous answers and specifically designed for CSV files can be found in this extension of mine on github:
https://github.com/rgrp/chrome-csv-viewer
Furthermore, with the new(ish) chrome webrequest API a direct approach is also now possible along the following lines:
Listen to onBeforeRequest (this has to be in a background script - see background.js)
Check if this is a CSV file (mimetype or file extension)
If so cancel the request and then display the data using xhr
A working version of this can be found in a branch of that extension: https://github.com/rgrp/chrome-csv-viewer/tree/4-webrequest-intercept
You could always look at the XML Tree code :).
If you only need to work with links, and not opening files from the address bar or File > Open, you could build a content script that adds a click event listener to every link.
In the event listener function:
Add e.preventDefault() in the first line to prevent the browser 'following' the link.
Using the link href value, get the data with XMLHttpRequest.
In the XMLHttpRequest callback, open a new tab and render content accordingly.
Obviously, in many ways, this is not a great solution:
you want 'normal' links to be handled as usual by the browser
how can you tell if a text file contains comma-separated values (for example) except by looking at the file extension which, of course, may not be reliable?
Are you specifically thinking of .csv files -- and/or other specific types of content?