How can I detect when the contents of a div are unloaded? - javascript

I have an application that navigates mostly with AJAX, and a section where a user can view information. I would like to track how long users are viewing different pieces of information. I want to assume that as long as they have the information loaded in the <div> they are "viewing" it. However when the user click on a link to "go to another section of the app" the <div> gets loaded with different content, the page doesn't actually redirect.
Does anyone have a solution for this, or at least some thoughts to help me see something I cannot see right now?
Thanks

Most analytics software will allow you track this. I have some experience with Google Analytics and it's something like:
ga.track("my-event", my_data);
Setting up a timer shouldn't be too hard. Put that code in the routine that handles content un/loading.

You should call some function when you update your content.
Since there is no "onchange" event for divs, you'll have to call your function after the ajax process: See this answer for more info.
However, if your content doesn't change according to ajax calls, you should trigger some event when your div changes.
Hope I helped you: without any code fragment I can't do more!

Related

One Modal, Ajax, and constantly updating data

I have reached a point in my project where I cannot figure out how to use Ajax to keep going. I am new to using it, but I'd like to think that I have a basic understanding of how it works.
I run a site where I take form data and post it into a database, then send it to a webpage where it displays in bubbles. Users can then click these bubbles and pop open a modal which has more detailed information than what is presented in the small bubbles initially displayed.
I've hit a wall where I don't know how to open a modal and have it live update with new information without closing, no matter what the bubble they click is (which can have different types based on different form information sent).
And to be clear, by bubble I just mean a compact div that when clicked opens the modal.
I've looked everywhere for solutions to this, trying my best to apply knowledge from other projects to what I'm trying to accomplish with to no avail. Suggestions are appreciated!
I'd suggest you to look at the load method this should be enough for what you're trying to do.
If you want a live update of your modal you have two ways to go about this:
Implement polling in AJAX. Send an AJAX request every X seconds to the server and have it update the <div>'s in your modal.
Use WebSockets. This is far more complex, and solution 1. is probably good enough.
This Stack Overflow post should help get you started: jQuery, simple polling example

How to create a page location in browser using javascript/jQuery?

I have a setup where I display a list of buttons and clicking on the buttons triggers a function that contacts a firebase database and gets the contents of a 'slide' that is to be shown to the user. The function then clears the content of the page and then creates elements from the data acquired from the database.
Now obviously, when I press back browser button once I've replaced the content, it won't take me back to the previous content. But I believe that my user's experience will be much better if it actually took them back to the list of buttons. I have two faint ideas on how to go about solving this problem but I'm lacking in specific details of how I can go about it.
Possible Solution 1:
Some way to dynamically create a new page using javascript and then serve it to the user.
Possible Solution 2:
Some way to simulate that the page has changed location. Maybe using anchoring links.
Let me know if you have any other solutions in mind or if you know how I should go about implementing these. Your help will be much appreciated. :D

I need users to proceed to the next page on mouseover in javascript with turn.js

I'm having a problem with the turn.js api.
Rather than using this for a book, I'm trying to use it for an ad I'm developing. Basically, I want to have the first page immediately 'uncover' the second page when the user hovers over the page, but can pull from the corner on page 2 (as normal) to go back to the first.
I'm thinking that I could set a function of onmouseover to mousedown or something like that. Or maybe something totally different.
Any help would be appreciated. Thanks.

HTML hide info bar during page reload

I need to reload an HTML page every second to monitoring the server status in a automatic control application. I'm able to do this using a Javascript timer, but I have a boring info bar on browser (I'm using Chrome, but I suppose that it is present also in others browser) that inform me that the page is reloading, and it is flashing every second. I would like to remove this info bar. Does someone help me ?
Thanks and regards,
Enrico.
Don't do this! This is a common case for AJAX - instead of refreshing the page. You'll be able to load data from the Server without reloading anything - on the fly!
Take a closer look at jQuery's ajax:
https://api.jquery.com/jQuery.ajax/
BUT: For monitoring purposes you should take a look at Node.js! This gives you the ability to handle requests and sockets in realtime. Ajax is useful for e. g. preventing page-refreshes but in your scenario i really recommend to use Node.js - its worth it!
To answer your Question:
Its not possible to access and control browser-related elements like the yellow info-tooltip on the bottom left when refreshing the page or hovering a link like it's also not possible to change the cursor's position.

Unobtrisuvely ask user for details

I am trying to figure out the best way to acompish "unobtrusive" forms for a user (within a web app).
The purpose: keep user on the site by not asking to fill unnecessary form in. Ask for the details as only when such are needed.
The requrements are:
User should provide additional details only when it is required (email to receive notifications, login required for account page, save credit card details when checking out).
User should not leave the current page providing the additional details.
The implementation would be fairly easy if all requests would be AJAX ones. It would be easy to analyse the response (401 or so) and show the appropriate lightbox-form.
I do not see how it can be done "the right way" with plain anchors and form submits as in both cases the user actually leaves the page (by following the link or submitting a form) and there is no way to analyse the response on the client side.
Converting all links and forms to AJAX ones would be just silly.
The closest analog to what I want to achieve is the default Basic Authentication dialog in most of the browser. But obviously that just doesn't fit my requirements.
Any creative suggestions how to do that for non-AJAX requests?
Regards,
Dmytrii.
In a page sense, where "page" refers to what the user sees and not what the URL is, I only can think of following ways to update independent parts in a page with JavaScript (and thus Ajax) switched off:
Frames
Iframes
Using held-open connections there are two more ways to update a page, however these do not work reliably in all cases:
Animated GIF
CSS DIV tags with absolute positioning.
Note that this needs that your Server can keep open a session for each person looking at the page, which can be thousands. If this does not work the only possible workaround is with FRAMEs and automatic refresh, which is somewhat clumsy.
As I think that you do not want to use Frames and you do not want to render animated GIFs, I explain the CSS DIV way:
When you load the page you do not finish loading it. Instead the connection is kept open by the web server and the script handling the connection waits for additional information to arrive. When there is additional data, this is sent to the browser by encapsulating it into additional DIV tags which can overwrite other parts of the page.
Using "style" in the DIV tag and CSS position:absolute these can overwrite other information on the page like a new layer. However you need either position:absolute or must add this data to the end of the page.
How does this work with forms?
Forms usually have a known size so you can put them into IFRAMEs. These IFRAMEs get submitted to the webserver. The script there notifies the other script that new data must be output, so the waiting script renders the response and displays it in the page while the script which took the submit redisplays the form with fresh values only.
How does this work with 404 and anchors?
I don't really know because this must be tested, but here is a hint how I would try to implement this:
We have 2 issues here.
First the URL must not point to other pages but back to a server script again, so the href is under control. This script then notifies the waiting script to update the page accordingly, for example by retrieving the page and sending it to your browser. The script can check for 404 as well.
Second you must hinder the browser to switch the page when clicking on the anchor. This probably involves some clever tricks using CSS, target and server side status codes (like "gone" or redirect to the current page, whatever) to keep the browser from switching the page. I am not completely sure if that works, but if you remember download pages, these show URLs which do not switch the page but have an effect (downloading the file). That's where to start to try to hack browsers not leaving the current page without using JavaScript.
One idea not followed here is not keeping the connection of the page open but the CSS file and send new css information to the browser which then "fills in empty stubs" using the CSS way. But I doubt that this works very well, most browsers probably will parse the CSS only after loading finished, but perhaps I am wrong.
Also note that keeping a connection open never finishes the page loading, so you will see the busy-logo spinning all the time, which is unavoidable with this technique.
Having said this all I doubt you get around JavaScript.
What I wrote here is very difficult to do and therefor usually is not used because it scales badly. And it is a lot more difficult than using JavaScript alone (that's why I explained it).
With proper AJAX it is much more easy to reach your goal. Also note that you do not need to change your page source much, all you need is to add a script which augments the page content such, that for example forms suddenly use AJAX instead of a direct POST with re-rendering the page. Things which cannot be detected easily then need some hints in the tags such that the tag scanner knows how to handle the tag. The good thing then is, that with JavaScript switched off your page still works - however it then "leaves the page".
Normal HTML just was not designed to create application-like web pages like we want to see today. This all was added using JavaScript.
About popup forms
The Basic-Auth-Handler reloads the page after the user enters something into this dialog, only if cancel is hit the current page is displayed.
But there are two ways to present additional query-popups in a page using JavaScript:
The first one is the javascript "prompt", like in following example:
http://de.selfhtml.org/javascript/objekte/anzeige/window_prompt_vor.htm
(Click on the "Hier").
The second one is "JavaScript forms" which are like popups within an HTML-page.
However I consider popups to be far too intrusive and bad design.
Ajax and JavaScript is the easiest way
Unfortunately using JavaScript is never easy, but if you think JavaScript is improper or too difficult, there is no other technique which is easier, that's why JavaScript is used everywhere.
For example your page onload-Script can cycle through all Anchor-Tags and modify them such, that clicking on them invokes a function. This function then must do something clever.
Same is true for Forms. Fields which can be modified (like the user's eMail address) then have two views, on is visible, the other one hidden. The hidden one is a form. Clicking on the eMail address then switches the view (disables the first div and enables the second), such that suddenly instead of the eMail address a text form field is there containing the eMail address. If you click on the "OK" button the button changes the look into a spinner until the data is submitted, then the view switches back to the normal one.
That's the usual way to do it using JavaScript and Ajax. And this involves a lot of programming until it works well.
Sorry for not shortening this post and missing code snippets, I am currently lacking time ;)
Hidden iframe.
Set target attribute of the form to the name of the iframe. use the onload event of the iframe to determine what is the response.
Or, if you really dont like any javascript, don't hide the iframe and instead present it in a creative manner.
CSS to hide an element
#myiframe { position:absolute; left: -999em; display: none; visibility: hidden; }
But normally, display: none is enough. This is just an overkill.

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