I'd like to be able to manually select text from cross-domain iframe with javascript on the frontend.
I know it's pretty difficult to achieve such result as the use of postMessage is required if I decided to use a 100% javascript solution. I'm opened to backend solutions (either php or nodejs)
Optimizely can access any dom element from the page, I'd like to understand how they are doing it. Is it because the user needs to install a widget on his website first? If yes, how does it works exactly?
Here's an example:
Reproduced from #2 of this answer:
Let's say you want to create an experiment on http://www.mypage.com ... The Optimizely Editor loads http://www.mypage.com inside an iframe and uses window.postMessage to communicate with the page. This only works if that page already has a snippet like [<script src="//cdn.optimizely.com/js/XXXXXX.js"></script>] on it. If that's not the case, the editor will timeout while waiting for a message from the iframe'd page, and will load it again via a proxy that actually inserts the snippet onto the page. This loading process allows the editor to work with pages that a. contain an account snippet b. do not contain an account snippet, or c. sit behind a firewall (c. requires the snippet.)
Related
I've read about how there are multiple methods to grabbing source code from another webpage via jQuery or using Cross-Domain Requests. What I want to try and do is make it so I grab a div that has different code each time a page is loaded and not the source code as a whole. So for example, the greater detail you see when you use 'inspect element' or a tool like firebug to dive deeper into the page code.
Would I be using one of the same methods?
Yes.
If you control BOTH domains you can add the Access_control_CORS
header to allow access of cross domain requests and use a
headless browser like phantomJS to grab a cached version of
rendered HTML page.
If you don't control both domains you will have to write a server
side proxy to grab the page and all its resources (you will have
to parse the page to get or rewrite links to images, javascripts,
stylesheets etc...) then run it through phantomJS to create a
HTML snapshot.`
source:
https://developer.mozilla.org/en-US/docs/Web/Security/Same-origin_policy
https://developer.mozilla.org/en-US/docs/Web/HTTP/Access_control_CORS
http://phantomjs.org/
NOTE: despite my best efforts, stack overflow is absolutely convinced these links are code. Sorry for posting as code.
So I have a site specific bookmarklet that create a page with a toolbar (using localstorage to set/get variables) and then creates an iframe for a destination site, say www.example.com. [Idea heavily borrowed from the wonderful RWD Bookmarklet (http://responsive.victorcoulon.fr/) ]. It works great, but I wanted to provide that a clickable link to that bookmarklet (because it is a pain to add a bookmarklet in an Ipad) but unfortunately that results in the obvious XSS cross-site problems since the link does not reside within www.example.com.
To improve this experience I was wondering if it would be possible to do have a popup (like twitter's) which would exploit an existing generic loadScript function currently present on www.example.com. From within the javascript console on www.example.com I currently can invoke a supervar.loadScript("http://dl.dropboxusercontent.com/s/blah/thefile.js") and it works. Which means I do not need to append or cross load the js into the iframe but I would need the iframe itself to invoke the supervar.loadScript call.
It is possible to invoke the supervar.loadScript on say a window.onload/document.ready type scenario or would the context of the popup code be pointing to about:blank/notexample.com in which case the supervar would not exist. Could window.postMessage be of any use?
UPDATE: Clarification
I am trying to have a button which would contain javascript code that in turn would open a new window/tab to a site but would be able to invoke a command on a variable that will be present when the DOM is ready.
Again, I'm quite new to XSS so I'm not sure if this is a security problem on the site. I'm not trying to access variables from one site to the next, just a means to load a userscript on a site without having to use a bookmarklet.
For a real test:
Visit: firsttaste.kraftcanada.com.
Open the javascript console and then enter: nitroWidget.loadScript("https://dl.dropboxusercontent.com/s/fcfbpfdmzrxywh9/mwolfe_alert.js")
This will execute the mwolfe_alert.js which merely contains an alert message.
Is there a way that I could create a clickable link on a site outside of *.kraftcanada.com which would create a popup/new tab that upon the {document,window,$}.onload/read would invoke the nitroWidget.loadScript?
I want my webpage to have two parts. The top part has a textbox. When the user types a URL into the textbox, the bottom part browses to the content of that URL. When the user clicks a link within the bottom part, the bottom part navigates to the new URL, and the textbox in the top part changes to the new URL. How can I do it?
NOTE: This behavior is the same as in Google Translate (e.g. here), but without any translation.
first problem..
Same origin issue
The only way to achieve what you are asking is exactly the way google translate does what it does - which is to use a server-side powered script as a proxy request:
http://translate.google.com/translate_un?depth=1&hl=en&ie=UTF8&prev=_t&rurl=translate.google.com&sl=auto&tl=en&twu=1&u=http://de.wikipedia.org/wiki/USA&lang=de&usg=ALkJrhgoLkbUGvOPUCHoNZIkVcMQpXhxZg
The above is the URL taken from the iframe that Google translate uses to display the translated page. The main thing to note is that the domain part of the URL is the same as the parent page's URL http://translate.google.com -- if both your frame and your parent window do not share the same domain, then your parent window's JavaScript wont be able to access anything within the iframe. It will be blocked by your browser's in-built security.
Obviously the above wont be a problem if in your project you are only ever going to be navigating your own pages (on the same domain), but considering you are proffering Google Translate as an example I'm assuming not.
What would Google do?
What the above URL does is to ask the server-side to fetch the wikipedia page and return it so that the iframe can display it - but to the iframe this page appears to be hosted on translate.google.com rather than wikipedia. This means that the iframe stays within the same origin as the parent window, and means that JavaScript can be used to edit or modify the page within the iframe.
next problem....
Rewrite the proxied content
Basically what I'm saying is that this can't be achieved with just HTML and client-side JavaScript - you need to have something to help from the server-side i.e. PHP, Python, Ruby, Lisp, Node.. and so on. This script will be responsible for making sure the proxied page appears/renders correctly e.g. you will have to make sure relative links to content/images/css on the original server are not broken (you can use the base tag or physically rewrite relative links). There are also many sites that would see this as an illegal use of their site, as per their site's terms of use and so should be black listed from your service.
final problem..?
Prevent the user from breaking away from your proxy
Once you have your proxy script, you can then use an iframe (please avoid using old framesets), and a bit of JavaScript magic that onload or ondomready of the iframe rewrites all of the links, forms and buttons in the page. This is so that when clicked or submitted, they post to your proxy script rather than the original destination. This rewrite code would also have to send the original destination to your proxy script some how - like u in the Google translate URL. Once you've sorted this, it will mean your iframe will reload with the new destination content, but - all importantly - your iframe will stay on the same domain.
too many problems!
If it were me, personally, I'd rethink your strategy
Overall this is not a simple task, and it isn't 100% fullproof either because there are many things that will cause problems:
Certain sites are designed to break out of frames.
There are ways a user can navigate from a page that can not be easily rewritten i.e. any navigation powered by JavaScript.
Certain pages are designed to break when served up from the wrong host.
Sites that do this kind of 'proxying' of other websites can get into hot water with regards to copyright and usage.
The reason why Google can do it is because they have a lot of time, money and resources... oh and a great deal of what Google translate does is actually handled on the server-side - not in JavaScript.
suggestions
If you are looking for tracking users navigating through your own site:
Use Google Analytics.
Or implement a simple server-side tracking system using cookies.
If you are looking to track users coming to your site and then travelling on to the rest of the world wide web:
Give up, web technologies are designed to prevent things like this.
Or join an online marketing company, they do their best to get around the prevention of things like this.
add a javascript function to your second frame -
<frame id="dataframe" src="frame_a.htm" onload="load()">
let the text box have an id - say "test"
function load()
{
document.getElementById('test').value=document.getElementById('dataframe').src
}
I'm sorry if this is a newbie question but I don't really know what to search for either. How do you keep content from a previous page when navigating through a web site? For example, the right side Activity/Chat bar on facebook. It doesn't appear to refresh when going to different profiles; it's not an iframe and doesn't appear to be ajax (I could be wrong).
Thanks,
I believe what you're seeing in Facebook is not actual "page loads", but clever use of AJAX or AHAH.
So ... imagine you've got a web page. It contains links. Each of those links has a "hook" -- a chunk of JavaScript that gets executed when the link gets clicked.
If your browser doesn't support JavaScript, the link works as it normally would on an old-fashioned page, and loads another page.
But if JavaScript is turned on, then instead of navigating to an HREF, the code run by the hook causes a request to be placed to a different URL that spits out just the HTML that should be used to replace a DIV that's already showing somewhere on the page.
There's still a real link in the HTML just in case JS doesn't work, so the HTML you're seeing looks as it should. Try disabling JavaScript in your browser and see how Facebook works.
Live updates like this are all over the place in Web 2.0 applications, from Facebook to Google Docs to Workflowy to Basecamp, etc. The "better" tools provide the underlying HTML links where possible so that users without JavaScript can still get full use of the applications. (This is called Progressive Enhancement or Graceful degradation, depending on your perspective.) Of course, nobody would expect Google Docs to work without JavaScript.
In the case of a chat like Facebook, you must save the entire conversation on the server side (for example in a database). Then, when the user changes the page, you can restore the state of the conversation on the server side (with PHP) or by querying your server like you do for the chat (Javascript + AJAX).
This isn't done in Javascript. It needs to be done using your back-end scripting language.
In PHP, for example, you use Sessions. The variables set by server-side scripts can be maintained on the server and tied together (between multiple requests/hits) using a cookie.
One really helpful trick is to run HTTPFox in Firefox so you can actually monitor what's happening as you browse from one page to the next. You can check out the POST/Cookies/Response tabs and watch for which web methods are being called by the AJAX-like behaviors on the page. In doing this you can generally deduce how data is flowing to and from the pages, even though you don't have access to the server side code per se.
As for the answer to your specific question, there are too many approaches to list (cookies, server side persistence such as session or database writes, a simple form POST, VIEWSTATE in .net, etc..)
You can open your last closed web-page by pressing ctrl+shift+T . Now you can save content as you like. Example: if i closed a web-page related by document sharing and now i am on travel web page. Then i press ctrl+shift+T. Now automatic my last web-page will open. This function works on Mozilla, e explorer, opera and more. Hope this answer is helpful to you.
I am quite new to web application development and I need to know how would I make other sites use it.
My webapp basically gets a username and returns some data from my DB. This should be visible from other websites.
My options are:
iframe. The websites owners embed an iframe and they pass the userid in the querystring. I render a webpage with the data and is shown inside the iframe.
pros: easy to do, working already.
cons: the websites wont know the data returned, and they may like to know it.
javascript & div. They paste a div and some javascript code in their websites and the div content is updated with the data retrieved by the small javascript.
pros: the webside would be able to get the data.
cons: I could mess up with their website and I don't know wow would I run the javascript code appart from being triggered by a document ready, but I wouldn't like to add jquery libraries to their sites.
There must be better ways to integrate web applications than what I'm thinking. Could someone give me some advice?
Thanks
Iframes cannot communicate with pages that are on a different domain. If you want to inject content into someone else's page and still be able to interact with that page you need to include (or append) a JavaScript tag (that points to your code) to the hosting page, then use JavaScript to write your content into the hosting page.
Context Framework contains embedded mode support, where page components can be injected to other pages via Javascript. It does depend on jQuery but it can always be used in noConflict-mode. At current release the embedded pages must be on same domain so that same-origin-policy is not violated.
In the next release, embedded mode can be extended to use JSONP which enables embedding pages everywhere.
If what you really want is to expose the data, but not the visual content, then I'd consider exposing your data via JSONP. There are caveats to this approach, but it could work for you. There was an answer here a couple of days ago about using a Web Service, but this won't work directly from the client because of the browser's Same Origin policy. It's a shame that the poster of that answer deleted it rather than leave it here as he inadvertently highlighted some of the misconceptions about how browsers access remote content.