time calculating script in javascript - javascript

Is there a way to know the total time one spends on a page opened in a browser using a python script? For example if one uses gmail, and is currently using it (i.e the page is non idle) can we know the total time for which the page was active?
Further explaining what I intend to do:
By active means I am actually using the page, be it reading it,
doing some typing or doing some mouse work.
It would be great if there would somehow be a way to exclude the
time spent in breaks, perhaps introduce some error?
I am not sure whether javascript would be apt for it, and am open to suggestions!

Short answer: I don't think so.
This isn't really an issue of whether Python can do it, it's to do with whether your browser exposes that information in a way that an external program/script can query.
There's also the issue of how you define/determine which page is "active". Is it sufficient that the browser window is currently the active window and the page is on the selected tab? Or would you expect some kind of interaction? What if I'm reading a long text and so am not making interacting with the page for a period of time, does that still count as active?
The fact that it's hard to detect activity even from the website point of view, doing so from a 3rd party application/script be it written in Python or any other language would be even trickier.
If you wish to explore this further, I'd say your best bet would be to write a browser extension/plugin. In fact, there may already be existing ones that may meet your needs.

That sounds highly browser and platform-specific.
So, in general "no".
If the browser has some kind of interface or "hook" support then it might be possible.

This isn't really Python specific.
The best I can come up with is leave something like "Google Analytics" to do all that sort of stuff for you, then using your choice of language, get the data you need from the API
Of course that might not be appropriate, and the rules for how long it deems the page viewed, etc... may not work, but at least it'll be consistent.

Related

Use of JavaScript in lieu of hyperlinks

As RIAs and SPAs (or web apps with heavy javascript usage) have become more and more popular, I've been running into systems that, instead of using good old a href hyperlinks, I see them utilizing constructs using onclick with JavaScript code that manipulates navigation. This is particularly true with images.
For example, instead of seeing something like this:
<img src="...."/>
<div ... onclick='SomeJsFunctionThatNavsToAnotherPage()'><img src="..."/></a>
What is the advantage of this? It makes it incredibly hard to trace where pages transition to when debugging or trying to root cause a bug. I can get the idea when the target to navigate can change (so yes, here you could use a function that computes to what page to navigate to.)
But I see this pattern even when the pages to navigate to are constant. I find this extremely convoluted and hard to test. Not to mention that there is always the browser-specific bugs that come from stuff (sadly in my experience from over-complexifying the front-end.)
But I am not a RIA/SPA developer (just backend and traditional web development). Am I missing the rationale behind this?
TO CLARIFY
My question is not for the case when we want to redraw the page or change current content without changing the current location. My question is for plain
old transitions, from page A to page B.
In such a case, why use onclick=funcToChangeLocation() over <a href="some location"/>.
This has been a pain for me when troubleshooting systems that are already written (for I wouldn't write them like that), but there could be reasons I am not aware of.
Again, my question is not for pages that redraw themselves without changing the browser location, but for navigation from one page to the next.
ALSO
If you are going to vote to close this question, at least leave a message explaining why.
If you are making a web application, sometime you don't want to redirect the user to another page, but you want to dynamically change the content of the page without refreshing the page. It has some advantages. It can be faster. You can easily keep the state of the page/application. You are not obligated to communicate with the server. You can update only a part of the page.
You can also dynamically request data to print the page. If you are displaying an user profile page, you can only ask a json object that represent the user. This json object is smaller than the whole page and will be dynamically rendered. It can help to reduce the data transfer between users and server when your bandwidth is limited.
EDIT: In the case of a simple page redirection, I think it's a bad practice and I cannot see an advantage. I think it obfuscate the website when the google crawler try to parse the website.
I once had a pretty successful web directory website. One day Google decided that "directories" are competing businesses and started penalizing sites that had links on directories. I used the method you describe to cloak outgoing links to try and trick Google.

Website doesn't work with Javascript turned off

So head to www.jabsy.com, with Javascript turned off.
Basically, I use some JQuery UI Dialogs, I use Javascript for all the bindings on the page...I pretty much use it for everything. Is that really a bad thing though?
Nothing really works without Javascript. Not even the Google Maps API.
Should I go out of my way to try and make the entire page work without Javascript? Is that even possible with my site? I wouldn't even know where to begin as I use Javascript for everything, so could I get some points? How many users actually turn off their Javascript these days?
Would it help to let the user know if they have Javascript turned off and make them turn it on before accessing it and provide them with directions how?
Yes, if your site requires JavaScript you need to let the user know that it is required.
For example:
<noscript>
<div>
You need to have JavaScript enabled to use this site.
</div>
</noscript>
You can provide more description as appropriate. A savvy user that sees this text is going to be able to then go in and turn on JavaScript for your site. A non-technical user might have trouble, but I would think most of them would be running with JavaScript enabled anyway (?).
According to data collected in 2007, about 3% of users in the US have JavaScript off. I'm sure that number is lower today.
It really depends on how critical the sections of your page that require JavaScript are. If there is a form that is mission critical, but controlled completely by JavaScript, you probably want to engineer a way for that form to do the same thing with JS on and off.
However, you have animated snowflakes on your background (for the love of God, don't really do this), it's not going to negatively affect someone visiting your site with JavaScript off.
Really, it all comes down to how important the information or actions are to your site. Turn off JavaScript and note all the things you can't do that are absolutely vital, then make them work.
Keep in mind there are several audiences that will not render your JavaScript:
Screen readers/accessible browsers
Console-based browsers (Text based browsers)
Search Engines (Google)
Your specific service (location-based messages) will be way too cumbersome to use without JavaScript (and its content is dynamic). Therefore, I see no problem requiring it. You should, however, point out that JavaScript is necessary to use your site (Preferably at the top, in really large letters). You can do that by including the alternative no-JavaScript content in noscript tags, i.e.
<noscript>
<div style="font-size: 200%;">You need JavaScript!</div>
</noscript>
However, most websites are content-based, like a company's homepage, stackoverflow or Wikipedia. These websites should be usable without JavaScript. Nowadays, even smartphones have excellent JavaScript support, but Kindle and regular phones are still too slow for JavaScript.
There is a line of argument that says sites should work without JS. Personally, I think that is tosh, unless you have a clientelle for whom this is liable to be an issue. JS is a reasonable thing to expect for many sites.
However, it is polite to let people know that this is a requirement, and inform them rather than just letting it not work. If your site is heavily JS dependent, then you may have made some mistaken design decisions, but it is probably not worth re-working it. If you monitor the number of people who get the "you need js" message, you will identify if it is proving a turn-off. I suspect it will not be an issue.
So build based on what you need, BUT tell people if they need to have things set.
You can use the <noscript><!-- html here if no Javascript --></noscript> tags and place content to be rendered in between if javascript is turned off.
I don't think there are many sites that will work with these days without it. It's more or less mandatory.

javascript find replace

I have a question about optimization, but more on the browser/client side.
I am catering to a few societies that need about 3 different languages. So I'm just putting my user's language type in the php session, and swapping out the text for selected areas on each page they navigate to. So, really nothing complicated.
However, I'm toying with the idea of letting javascript do the find/replace of the selected texts on each page.
There are a few ways to skin this cat, and I've done them all, and they work. However, I do have a few hundred pages, and many words to replace with the correct language text.
If I were to go the Javascript route, does anyone have an opposing view to this? And if so, why? I'm interested in letting the user's browser do the work, rather than my servers constantly finding and replacing, or creating new CONSTANTS for each language specific situation.
I'm worried about their browsers getting slower. But that could be a very small problem.
For those individuals who love to get specifics, here's what I would do with javascript.
I would load a languages.js file with all appropriate word translations for any language I implement. Instead of running a huge find/replace on each page load, I'd localize the find/replace to the specific page, or possibly narrow an element to have an attribute that my scripting would load in the the DOM and perform a find/replace on that alone.
I'm open to better ideas.
Also, for those people who find "over-optimization" useless or "over-doing-it", please don't mention anything. This is for fun and not a critical decision item.
thanks guys!
Well, on the pro side, yes, you are offloading some of the work to the client, but I don't think that's going to make any real difference. You're probably talking about a tiny percentage of the overall performance of the site. The only way to know of course is to test it.
On the con side, you'll be increasing the bandwidth it takes to load your site, since the user will need to load the page plus the language file. It will be cached, if you set it up right, so that's probably not a huge concern either.
Another con is that this will make your site depend on javascript. A non-scripting visitor won't get the translation, and that includes search engines. Whether that matters to you depends on the nature of your site, but in general, that's a pretty big negative.
You'd also have to watch out for "flashing" of the non-localized language. It'd look horrible if the page loaded and then a split second later the language changed to something else. If you are doing the swapping from the DOM ready event ($(function() {}) in jquery, for example), it's probably too late. You could do it from a script you put at the bottom of the page, and that'd probably be ok, but even then, it may depend on the browser and the structure of the markup, not to mention the user's bandwidth and whether the server sends the content in chunks.
I think it comes down to what fits your needs best. Sorry that's not much of an answer, but it's an accurate one I think :)
I agree it is important to keep your server from overload. I would solve the problem one of two ways
Use your suggested javascript find and replace, whilst the javascript is working, have a loading.gif spinning round with a message to the effect of 'translating' nearly to explain to users why they must wait. If you are doing a word by word translation, you have to be careful about causing a browser like IE or to moan about having to do work 'The page has become unresponsive'; I would suggest running a setInterval(Translate(), 1) where translate translates a set number of words at a time so the browser doesn't think your script is going in an endless loop.
Provided the same sections are translated for all foreign visitors, you could make a PHP script that makes new, translated pages next to the originals. The translated pages could include the translator.php script to do a quick check to see if the original page has changed to decide whether or not to make a new translated page. This would not mean translating a page every time it needs to be viewed in a foreign language, but only a little check to see if the original had changed - putting less load on your server and none on the client side browser.
Personally I would implement 2 if possible to be more low-power-browser friendly (such as mobile devices) but in practice either would do and it's an interesting problem.

how to restrict user to copy web content

I am creating a web site and my client demands to restrict user to copy TEXT displayed on the web page.how can I do that? I am using PHP and HTML in my application.
Not trying to be rude, but why do people keep asking this? If you want people to be able to see the information, then you cannot prevent them from copying it. Any kind of javascript nonsense to prevent right-clicking or selection or whatever else will not stop determined thieves and will annoy legitimate users.
As mentioned by every answer previously, there's no way to prevent someone from being able to use the copy from your site. Even if you use methods to restrict direct copy and paste, there are always screenshots, OCR or good old writing by hand.
Looking at it from a different perspective...if the content is sensitive and your client doesn't want it distributed, you COULD add it to a section of your site that requires registration and authentication to access. By doing this you could require that users agree to terms and conditions on registration which explicitly deny permission to reproduce any of the content from the site.
Just a thought.
As every other answer has said, there is nothing technically you can to to prevent people from copying the text of your page. For the text to be display to the user, you must send it to the user's computer, which means they can copy it.
However, you can legally prevent them from copying the text with a service like CopyScape
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you can force people to call a phone number to hear the text of your website, a great solution if you do not want people to copy/paste the text of your webpage
Basically, you cannot. Even if there was a way to restrict user from copy & paste the text, they can always just grab the screen and translate it somehow into text.
I'd recommend not to try restrict users in any way. It's not really friendly and people usually hate it. If you want to create some private content, just make people to log in, do some ACL check and hope that they won't copy it somewhere else. You could also consider using some kind of license to prevent people from "stealing" your content.
Even if he was to build the system in flash the user could still hand write out the content if they desperately wanted it, like everyone else said its impossible to stop a determined person from getting your content, unless of course you don't display it.
No, AFAIK, there is no way you can achieve that. Unless you're building the whole thing in Flash or other non-HTML plugin contents.
The short answer is that you can't (easily) do this - if it's visible in the browser then it is obtainable somehow. This is particularly the case if you are just displaying text.
And it all gets back to "Why"? If the information is secret, don't show it to someone in the first place. If you're concerned about copyright violation, as others have said, once someone sees the text, even if you somehow came up with a brilliant technical solution that prevented them from copying the text in any way (which I doubt is possible), they could always write it down by hand, or take a picture of the screen with a digital camera and then OCR it. In the digital age, your protection against copyright violation is more legal than technical: if somebody steals your material and resells it, sue them.
Depending on the nature of your material, you may be able to make it awkward for people to get it all on one screen. Like, if you were running an on-line phone book and you were afraid of people stealing your listings, instead of displaying some large number of listings on one giant page -- all the "A"s or whatever -- you could require people to enter search terms and only show two or three possible hits at a time. Then if someone wanted to steal your listings, they would have to spend thousands of hours entering every imaginable search term. Now that I think of it, I was using some phone book site the other day that gave me a listing of names and addresses that were possible matches, but then I had to click on each one to get the phone number. At the time I thought "dumb nuisance", but now it hits me: they probably had the same idea that I briefly thought was original. Anyway, if your material is a database of individual factoids, this could be practical. If it's an article on the economic history of Lithuania or some such, making the user seach for it in tiny pieces is just going to make people abandon you and look elsewhere.
Personally, I've taken the philosophy that I just don't care. I've had many occassions when I've done Google searches on subjects that interest me and turned up articles that I've written, on sites that never asked my permission. I once even found an article that I wrote on one of those pre-written student papers web sites. (Not that any student would just paste his name on it, print it off, and hand it in, of course. They are "for research purposes only". I'm sure if they knew of students claiming this as their own work they would take down the site immediately.) So an article that I published on the web, available to anyone for free, these people were now charging dishonest students $25 to download! My reaction was, Way cool! It's one thing when others quote you, but you've really reached the big time when others plagiarize you!
This is not possible.
You cannot prevent someone from getting the information if you're sending it to them so they can see it. A user can simply view the source of the HTML and see what the text is and copy it from there and there's nothing you can do to stop them.
Implementing anything in JavaScript is completely ineffective since anyone can just disable JavaScript in their browser and get around it, and you'll only end up annoying your users.
The only way to prevent someone copying the text from a web page is to not put it on the web page in the first place.
If you presented content via images, or flash, and prevented the ability to save as that might be a solution. I found some resources you might find useful in protecting images here and some information on "preventing" print screen here.
Unfortunately, there is no easy solution for your question, as once the content is delivered to the user, they have ultimate control over the information (who's preventing them from taking an actual picture of the site?).
Well, the PHP has nothing to do with it, as that's server-side. You might be able to cook up something in javascript (it's fairly easy to disable right-click; it may also be possible to disable text highlighting), but it's fairly easy to get around this. Failing all else, the user might view source, though that can be encrypted too:
document.write(base64decode('encoded string containing entire HTML document'));
This is, frankly, both annoying and pointless. Anything that's available to the user can be taken somehow. Even flash isn't immune. (There are browser plugins available to take videos out of flash.)
You may want to look at your target audience as well to help determine how you want to make it harder (since you can't realistically prevent it)..
For the simple user just disabling the right click may be good enough to prevent it. Slightly more work would be to do as others had suggested and create an image. With the image you'd probably want to set a background-image on a DIV or something since you can easily drag images, using the IMG tag, straight from the page onto you desktop, or wherever. From there you could use Flash, or some other RIA, or maybe even SVG/VML..
Anyone who knows how to do a screen capture really narrows down what you can feasibly implement :(
<script type="text/JavaScript">
//script to bar copying of website contents
function killCopy(e){
return false
}
function reEnable(){
return true
}
document.onselectstart=new Function("return false"){
if (window.sidebar){
document.onmousedown=killcopy
document.onclick=reEnable
}
};
</script>

Is it safe to assume Javascript is always turned on? [duplicate]

This question already has answers here:
Closed 13 years ago.
Duplicate:
Do web sites really need to cater for browsers that don’t have Javascript enabled?
Only supporting users who have Javascript enabled.
How common is it for Javascript to be disabled
How many people disable Javascript?
I've been doing web applications on and off for a few years now and each application I write seems to have more javascript than the previous one.
A frequent comment is: "But what if the user turns off Javascript?".
I take the point, but I've never actually seen a user do this. Not once.
Have you?
This comes up about every other week or so. Did you search first?
See these:
https://stackoverflow.com/questions/121108/how-many-people-disable-javascript
https://stackoverflow.com/questions/379735/how-common-is-it-for-javascript-to-be-disabled
Only supporting users who have Javascript enabled
Do web sites really need to cater for browsers that don't have Javascript enabled?
The main points are:
Google doesn't use javascript when indexing
Mobile browsers (smart phones like the iPhone) sometimes have bad or non-existent javascript
Screen readers don't do javascript well, if at all, and many developers are legally required to support them.
Thanks to filters like NoScript, the number of people browsing with javascript disabled (at least initially) may actually be going up.
So yes, you still need to worry about it.
It depends entirely on what sort of coverage you require.
Do you need 80% 90% 100% of users to be able to use your site / application?
People DO turn off Javascript. The question is, does your site need to work for those people? Can it just tell them to turn it on if they want to continue?
Yes, it happens.
NoScript is a Firefox add-on - downloaded by plenty of people.
No Script
You should always make sure your site works without javascript.
People turn javascript off for security reasons. Companys sometimes have javascript forced off at their inhouse computers. Also spiders don't have javascript so your site not working without javascript is bad SEO practice.
5% of users have JavaScript turned off.
It has become a standard at my office (for better or for worse) to assume that the user has JS installed and turned on. The number of people who have it turned off is getting smaller and smaller every day, but this still doesn't mean that you should forgo performing the necessary validation for submission on the server side as well just in case (as well as some other scenarios).
I would say that it is not safe to assume javascript is always on, but it is safe to REQUIRE javascript be turned on.
In other words, you don't need to jump through hoops to make something work without it, just display a message or redirect.
Javascript is an essential technology, and it's not unreasonable to require it.
It's rare, but it's possible. If you are launching an application for "everyone" to use on the internet, then yes, you'll have to prepare for such an event. It really depends on your target audience, but the safest assumption is that someone will have it turned off.
From a security perspective, you definitely need to handle this situation, as turning off JavaScript (or worse yet hijacking the scripts you wrote) is an easy to bypass business logic and validation, if it isn't double checked on the server. Requiring it to be turned on is not a good enough defense for stopping people in this situation. Remember you're requesting that the browser tells you what it enabled and disabled. The user (or attacker in this case) is in control of the browser, and you can't trust what it says as it's easy to modify the HTTP headers.
Depends on who your target audience is. Some users turn off JS for various reasons. Usually, they will enable it for individual sites that need it, but they might not do that if you don't tell them they need it.
If your site just fails to load correctly, they'll assume it's broken. If it shows a "you need JS to view this page" message, then at least they'll know what to do.
Some will then enable Javascript for your site specifically, but some won't, and they simply won't be able to use your site, unless it is functional without Javascript.
It's rare, but it happens. It really depends on who your user base is. If it's for corporate users, a lot of them have default security settings with javascript disabled. If it's for... pretty much anyone else, odds are they'll have it turned on.
I run by default with javascript off for new sites (NoScript) plugin. I think many tech-savvy users do the same. At least the ones who are paranoid about XSS attacks.
It is best practice to code for users that have JavaScript turned off.
As web developer your goal should be to provide the core basic functionality (without JavaScript). This enables all users to fully use your site. Then through the use of JavaScript, in a process known as "progressive enhancement", spruce up elements of the site for users that have JavaScript turned on.
And in the case where JavaScript is off...your site should gracefully degrade.
Web development is one of those arenas where you can't expect anything. Code for all users to maximise your site's accessibility.

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