Track when user hits back button on the browser - php

Is it possible to detect when the user clicks on the browser's back button?
I have an Ajax application and if I can detect when the user clicks on the back button I can display the appropriate data back
Any solution using PHP, JavaScript is preferable. Hell a solution in any language is fine, just need something that I can translate to PHP/JavaScript
Edit: Cut and paste from below:
Wow, all excellent answers. I'd like to use Yahoo but I already use Prototype and Scriptaculous libraries and don't want to add more ajax libraries. But it uses iFrames which gives me a good pointer to write my own code.


One of my favorite frameworks for doing this is Yahoo!'s Browser History Manager. You register events and it calls you back when the user returns Back to that state. And if you want to learn how it works, here's a fun blog entry about the decisions Yahoo! made when designing it.


There are multiple ways of doing it, though some will only work in certain browsers. One that I know off the top of my head is to embed a tiny near-invisible iframe on the page. When the user hits the back button the iframe is navigated back which you can detect and then update your page. Here is another solution.
You might also want to go view source on something like gmail and see how they do it.
Here's a library for the sort of thing you're looking for by the way


There's no way to tell when a user clicks the back button of presses the backspace key to go back in the browser, however there are other events that happen in a certain order which are detectable. This example javascript has a reasonably good method for detecting back commands:
The traditional way, however, is to track user movement through your site using cookies or referrer pages. When the user goes to page A, then page B, then appears at page A again (especially when there's no link on B to A) then you know they went back - A can detect this and redirect them or otherwise.


The Yahoo User Interface Library, my personal favorite client-side JS library, has an excellent Browser History Manager that does exactly what you're asking for.


The simplest way to check if you came back to a cached version of your page, which needs to be refreshed, is to add a hidden input element that will be cached, and you can check if it still has its default value.
Just place the following inside your body tag. I place mine right before the end tag.
<input type="hidden" id="needs-refresh" value="no">
<script>
onload=function(){
var e = document.getElementById("needs-refresh");
if (e.value === "yes")
location.reload();
e.value = "yes";
}
</script>


I set a variable $wasPosted in $_SESSION with value false.
All my posts go via the same php file, and set $wasPosted to true.
All header(location:) requests are preceded by setting $wasPosted to true.
If $wasPosted is false then the page was loaded after use of the backward or forward buttons.


The dojo toolkit has functionality to deal with this in javascript. I don't think there is any good way to handle it in pure PHP.
Here is the docs page they have: http://dojotoolkit.org/book/dojo-book-0-9/part-3-programmatic-dijit-and-dojo/back-button-undo

Related

Laravel's flash data available after browser back button clicked [duplicate]

So the SMEs at my current place of employment want to try and disable the back button for certain pages. We have a page where the user makes some selections and submits them to be processed. In some instances they have to enter a comment on another page.
What the users have figured out is that they don't have to enter a comment if they submit the information and go to the page with the comment and then hit the back button to return to the previous page.
I know there are several different solutions to this (and many of them are far more elegant then disabling the back button), but this is what I'm left with. Is it possible to prevent someone from going back to the previous page through altering the behavior of the back button. (like a submit -> return false sorta thing).
Due to double posting information I can't have it return to the previous page and then move to the current one. I can only have it not direct away from the current page. I Googled it, but I only saw posts saying that it will always return to the previous page. I was hoping that someone has some mad kung foo js skills that can make this possible.
I understand that everyone says this is a bad idea, and I agree, but sometimes you just have to do what you're told.

Don't do this, just don't. It's bad interface design and forces the user's browser to behave in a way that they don't expect.
I would regard any script that successfully stopped my back button from working to be a hack, and I would expect the IE team to release a security-fix for it.
The back button is part of their program interface, not your website.
In your specific case I think the best bet is to add an unload event to the page that warns the user if they haven't completed the form. The back button would be unaffected and the user would be warned of their action.

Nah, you're doomed. Even if you pop the page up in some different browser and hid the back button, there's always the Backspace key.
The problem with marketing guys and analyst types is that some of them do not understand the fundamental concept of the web being stateless. They do not understand that the page is totally, totally unaware of the browser using it and absolute control of the browser is totally outside the capability of web pages.
The best way to discourage your users to hit the back button is to make sure that your page loses all its data when they press back, e.g., the comment page is the only point where the data can be saved, and if they do press the back button they have to do everything all over again (think along the lines of pragma: nocache).
Users will complain, sure, but they are the reason that this godforsaken requirement exists, right?

I've seen this before:
window.onBack = history.forward();
It is most definitely a dirty hack and, if at all possible, I would attempt to not disable the back button. And the user can probably still get around it quite easily. And depending on caching, there is no telling if the server code will be processed or if the cached page with JavaScript will run first.
So, yeah, use at your own risk :)

I came up with a little hack that disables the back button using JavaScript. I checked it on chrome 10, firefox 3.6 and IE9:
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<title>Untitled Page</title>
<script type = "text/javascript" >
function changeHashOnLoad() {
window.location.href += "#";
setTimeout("changeHashAgain()", "50");
}
function changeHashAgain() {
window.location.href += "1";
}
// If you want to skip the auto-positioning at the top of browser window,you can add the below code:
window.location.hash=' ';
var storedHash = window.location.hash;
window.setInterval(function () {
if (window.location.hash != storedHash) {
window.location.hash = storedHash;
}
}, 50);
</script>
</head>
<body onload="changeHashOnLoad(); ">
Try to hit the back button!
</body>
</html>

Do you have access to the server-side source code? If so, you can put a check on the first page that redirects to the second page if the information has been submitted already (you'll need to use sessions for this, obviously). At a former job, this is how we handled multi-step applications (application as in application for acceptance).

Could you move the comment to the previous page and make it a required field there?
Disabling the back button will not work.

Because of the security isolation of javascript in the browser, you cannot change what the back button does.
Perhaps you could store something in the user's session that indicates that a comment is needed, and have any page in the app that the user tries to load redirect to the comment page?
What if the user closes their browser when he/she gets tot he comment page?
I know that you have not been given a choice here, but since what they are asking for seems to be impossible...
Perhaps you could just not consider the item as completed until the user enters comments. Thus, you would need to keep track of both in-progress items and completed items, and make that distinction in the UI, but this might be the most robust method.
Or just put the comment field on the form page?

What the users have figured out is
that they don't have to enter a
comment if they submit the information
and go to the page with the comment
and then hit the back button to return
to the previous page.
Then they are probably also smart enough to type 'no comment' into the comments field.
You can try to force people to add comments, but you will probably just end up with bad unusable software, annoyed users, and still not get comments. This is usually a good time to take a step back and reconsider what you are doing from the users' point of view.

Disabling the back button seems kind of a "brute force" approach.
Another option would be that you could jump out to a modal dialog that doesn't have command buttons, walk users through the workflow, and close the dialog when the process is complete.

You should secure your application against double submission instead of breaking user interface to hide the bug.

There simply is no reliable way to do this. You cannot guarantee that 100% of the time you can stop the user from doing this.
With that in mind, is it worth going to extremely exotic solutions to disable "most" of the time? That's for you to decide.
Good luck.

AS a simple solution: try this one. Insert an update panel and a button in there and use javascript to hide it and then press it on page load. Yes I understand that it will cause your page to post back on load and may not work if javascript is disabled but certainly will help you achieve a half decent response to the back button issue. Andy

You can prevent them from going back to the previous page. location.replace() replaces the current page's history entry with a new page, so...
page1.html: user clicks a link that goes to page2.html
page2.html: user clicks a link that calls location.replace('page3.html');
page3.html: user clicks back button and goes to page1.html
This may not fit well with doing a POST, but you could post the data to a web service via AJAX, then call location.replace()

If you are starting a new web app from scratch, or you have enough time to rework your app, you can use JavaScript and AJAX to avoid the browser's history, back, and forward functions.
Open your app in a new window, either before or immediately after login.
If you wish, use window options to hide the nav bar (with the back and forward buttons).
Use AJAX for all server requests, without ever changing the window's location URL.
Use a simple web API to get data and perform actions, and render the app using JavaScript.
There will be only one URL in the window's history.
The back and forward buttons will do nothing.
The window can be closed automatically on logging out.
No information is leaked to the browser history, which can help with security.
This technique answers the question, but it also contradicts best practice in several ways:
The back and forward buttons should behave as expected.
An app should not open new browser windows.
An app should still function without JavaScript.
Please carefully consider your requirements and your users before using this technique.

I don't see this solution :
function removeBack(){
window.location.hash="nbb";
window.location.hash="";
window.onhashchange=function(){window.location.hash="";}
}

Reload Methods: Complete Ajax Solutions

My web application utilizes page reloads in places where the page structure changes.
For content changes initiated by the user it is all handled by Ajax.
However I'm planning on removing all the page reloads and replacing them with ajax calls that simply update the page using innerHTML for the body and head tags.
To do this I know have to manually call functions that are normally called by the onload event.
When I am done I will have a complete ajax application. My question is, is this standard practice now....I see a lot of applications where you do something and the whole page reloads, where even common elements are reloaded.
For example go to Apple.com and hit on the first button you see "Store"...you will see the whole page reload even the menu bar that does not change is reloaded wasting bandwidth..
Because I don't see other people using complete ajax solutions...I wonder if I am headed down a wrong path.
My question?
Is a complete ajax based web application best practice? (of course file uploads aren't supported, omitting this, is it best practice).
If so why do big sites not do it? I see few sites that actually employ ajax instead of page reloads.

There are a number of reasons not to go fully ajax. A few are:
If the user refreshes the page they'd be sent back to the home page;
if they pressed the back button, they'd go back to the previous site
they visited.
Search engines won't be able to index anything past the home page.
Anyone without javascript enabled or on IE 6 (or it's equivalent) wouldn't be able to use the site.
Lastly, it can be hell to debug a problem -- I went full ajax on a project a while ago and ended up regretting it.
If none of the above are important to your project, and you're looking to do something different, then by all means -- the real question you need to ask is "does the added complexity justify the savings in bandwidth?".

The concept of ajax is reload certain content of the page when you don't need to change all the content.
Your example of apple.com: it isn't a best practice to use ajax in navigation, because the history of browser don't handle this (use the back button of the browser and the navigation will not respond if you use ajax, keep that in mind).
If you have a box with testimonials and want them to change from time to time, so it's a good place to use ajax, avoiding the whole page to reload.
You can also have a static page with all testimonials to let search mecanisms to index that content.
Example of big sites? The search of google. When you type only the box of results is reloaded to view one preview.
So you have to choose when use and when not use ajax.

PHP - Allow users to vote without loading another page/reloading the current page

I want to put Thumbs up/Thumbs down buttons on my website.
There will be quite a few of them displayed at once, so I don't want to have to do a POST and reload the page every time the user clicks on one.
I thought of using re-skinned radio buttons to choose Thumbs up/Thumbs down, but that would require the user to click a submit button.
So how do I do this? I am open to using JavaScript or some other form of Client-Side scripting, so long as it is built in to most/all web browsers.
Thanks!
YM

I would take a look at using jQuery, http://jquery.com/ It is a WIDELY used library and there is tons of support for it both here and # jQuery's website.
You could easily assign all those thumbs to do an ajax post to a save page with the correct id and the user would not know the difference

You're definitely going to need to use JavaScript on this. Well, there are other client-side languages that could technically do the job (ActionScript, for example), but JavaScript is definitely the best way to go.
Look into AJAX (Asynchronous JavaScript And XML). This is just a buzzwordy way of saying use the XMLHttpRequest() object to make page requests with JavaScript without reloading the page. Here's a good tutorial: http://www.w3schools.com/ajax/default.asp . Note that, despite the word "XML" being in the title, you don't have to use XML at all, and in many cases you won't.
What you'll basically do is this:
Have your thumbs-up and thumbs-down buttons linked to a JavaScript function (passing in whether it's a like or dislike via a function argument).
In that function, send a request to another page you create (a PHP script) which records the like/dislike. Optionally, you can have the PHP script echo out the new vote totals.
(optional) If you decided to have your PHP script output the new results, you can read that into JavaScript. You'll get the exact text of the PHP script's page output, so plan ahead according to that -- you can have the PHP script output the new vote totals in a user-friendly way and then just have your JavaScript replace a particular div with that output, for example.

AJAX VS PHP for dynamic web pages?

Why use AJAX for dynamic web pages when you can do it only with php?

The main reason to bother with AJAX is User Experience (UX).
Now AJAX won't necessarily improve UX in every single instance so in a lot of places sticking with pure PHP is perfectly okay.
But imagine the case where you have a text field on the site and a link to vote on something. Kinda like this site. When you add AJAX your users won't loose the text they entered in the textfield when they decide to vote on the link! How incredibly useful!
So if you care about your user's experience it is a good idea to use AJAX in situations like that.

PHP creates and outputs the Content to the Client Browser as it's a Server-Side Language and that's what it was built for, so on a request your code will access database, files etc. and then output the constructed html/text to the client.
Ajax just gives the User a more Desktop like feel. For example deleting a record and instead of the entire page reloading just letting the one element disappear from say a list and letting the server know that the record is to be deleted. But Remember to let the User know when you are busy sending data to the server (With a progress bar in .gif format for example). As lot's of user feel that if nothing happens on the screen to notify them, that the application is frozen which means they will either reload the page or just try to click the button again.
But you will need to provide some sort of compatibility with browsers that have Javascript disable and thus cannot use your AJAX functions, just something to keep in mind.

AJAX stands for Asynchronus Javascript and XML, meaning that a page can get new data, without having to reload a page.
PHP cannot send data without reloading the whole page. A user has to press a button, to send data.
An example of AJAX is for example google suggestions or the tag suggestions on this website.

Simple question about javascript history.go

I have a classifieds website.
In every classified, there is a back link which simply takes the browser back one step.
This is because when users search classifieds, and click on one to view it, they can easily go back with a link also (instead of only the browser back button).
Here is the problem, if the classified is entered directly into the adress bar of a browser, or if somebody bookmarked a classified, then this back-link would take them someplace else...
Is there any way of making sure that the previous page is a certain page (index.php in my case)?
This way I would only display the back link if the previous page was index.php...
Thanks

You can't query history data. A slightly better option is to read the Referrer server variable and create your "Back" link to it. It's not very much stronger than history.go(), though. Try using a common index page instead.

Why not just insert a link to index.php directly? That way you have complete control over the target of the link. No need for JavaScript.

You should track their session within PHP or whatever language you're using in order to have an effective "back" button.
You could pull the data with document.referrer but that will not always give you the previous page. Sadly I am not sure of a way to achieve a "Back" button via javascript without using some kind of scripting language to track a user either via cookie or session.

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