I am creating a notifications script that check a database for changes and returns then in a javascript custom popup.
I have successfully made the jquery ajax loading and processing script, and php long polling page.
all this worked great aside from the fact the long lasting request prevented any other ajax loaded content from working. I found that the way to stop this was to move it onto a different subdomain.
however this causes issues with the js "Same Origin Policy", all the possible ways of doing this seem to not work with long connection speeds or the other option php proxy defeats the whole point in seperate domains.
Does anyone have any ideas how to do this, or any help at all.
Thanks
Oli
Another thing you could try is padded json. You can create a dynamic script at some url which accepts GET parameters, like sub.domain.com/jsonp.php?var=value which returns something like:
var response={a:1,b:2}
And you could dynamically load a <script/> element with that url as the source. The variable set in the jsonp will be accessible to other scripts, and is not subject to SOP.
There is no way for solving this in a easy way.... the easiest way that I found is the following:
Create an IFrame (yes I know), this IFrame has to load a page coming from the subdomain (sub.example.com/base)
Both pages the main and the one loaded in the IFrame has to set the document.domain to '.example.com' after this you would be able to
Make the long polling from the IFrame without occupiying one of the two domains connection
Communicate between the main page and the IFrame, so you can just leave the IFrame for long-polling and then call a callback to the parent
This also solves another problem that you would have later that is the browser loding spinning wheel spinning until the first long poll is finished....
Related
I've been researching this topic for the past few hours with little success. I wish to redirect from the content of a frame, to the parent of the frame using php. .. The only reason I think it's possible is because I disabled javascript on my browser and phpMyAdmin was still able to redirect me when the session ran out of time.
I also realize it is most likely not possible, given that frames are a client-side thing, and php is not.
That in mind, I'm wondering how phpMyAdmin does it. I do not wish for js to be required for my web application.
If an iframe has links which looks like this:
Some page
it should work, as long as both pages or on the same domain.
Alternatively, take a look at this answer: How to force link from iframe to be opened in the parent window
I want to load external websites inside div and make it a bit smaller to accommodate inside div more properly.
just like Google search do
I tried this:
$("#targetDiv").load("www.google.com");
but it is not working.
I tried iframe but it has still 2 problems:
scrolling is still enabled by pressing arrow keys & PGUP PGDOWN
how to make contents inside iframe smaller
Don't know which method i should use
which is more optimized
or any alternative?
What you're trying to do is not going to work. Unfortunately, JavaScript isn't allowed to make cross-domain requests for security reasons (reference: http://en.wikipedia.org/wiki/Same%5Forigin%5Fpolicy).
If you create a script written in PHP that resides on your own server that submits the request, that could work but the user wouldn't have a valid session and there's a risk that the URL (links) from the other site won't work if they're relative.
Example:
$('#targetDiv').load('load.php?url=www.google.com')
You could also have a look at jquery-crossframe. I've never used it but it claims to do what you're looking for.
The best option is to use an iframe element.
You are not going to be able to load a cross domain ajax call like that with jquery. from http://api.jquery.com/load/
Additional Notes:
Due to browser security restrictions, most "Ajax" requests are subject to the same origin policy; the request can not successfully retrieve data from a different domain, subdomain, or protocol.
If iframe is not an option you can retrieve the data via an ajax call to a php page using curl.
Francois is right in that your ajax requests are restricted to same origin policy. That means you cannot load contents from other websites directly. What your are trying to achieve, however, is possible if your source supports JSONP. If you want to specifically load google search engine results check out Google Custom Search API
I'm new to YQL, and just trying to learn how to do some fairly simple tasks.
Let's say I have a list of URLs and I want to get their HTML source as a string in javascript (so I can later insert it to a database via ajax). How would I go about getting this info back in Javascript? Or would I have to do it in PHP? I'm fine with either, really - whatever can work.
Here's the example queries I'd run on their console:
select * from html where url="http://en.wikipedia.org/wiki/Baroque_music"
And the goal is to essentially save the HTML or maybe just the text or something, as a string.
How would I go about doing this? I somewhat understand how the querying works, but not really how to integrate with javascript and/or php (say I have a list of URLs and I want to loop through them, getting the html at each one and saving it somewhere).
Thanks.
You can't read other pages with Javascript due to a built-in security feature in web browsers. It is called the Same origin policy.
The usual method is to scrape the content of these sites from the server using PHP.
There is an other option with javascript called a bookmarklet.
You can add the bookmarklet in your bookmarks bar, and each time you want the content of a site click the bookmark.
A script will be loaded in the host page, it can read the content and post it back to your server.
Oddly enough, the same origin policy, does not prevent you to POST data from this host page to your domain. You need to POST a FORM to an IFRAME that has a source hosted on your domain.
You won't be able to read the response you get back from the POST.
But you can poll with a setInterval making a JSONP call to your domain to know if the POST was successful.
I am currently investigating a double request problem on my site. Not all the time, but sometimes, a requested page will in fact load twice...which is not a problem really until it is on a page with PHP that inserts stuff into my db on request (my tracking script).
I have read that an empty src in an image tag, and an empty url() in a css background could potentially cause the page to be requested twice.
However, I can't find any problems with those.
Is there anything else that could be causing something like this?
ANSWER FOR MY SITUATION
After some extensive research, it turns out that in my case specifically, the second request has been coming from the user agent "Mediapartner-Google". I began to notice that on pages that serve an Adsense ad, I could expect a secondary visit from this crawler within seconds after I visit the page myself.
This doesn't seem to be happening on pages without Adsense ads.
I am going to mark an answer below, because it seems like for most situations, those are the correct things to check.
I have sat beside people whom I would swear knew better than this, and watch aghast as they double-clicked on every hyperlink in our app.
Didn't take long to figure out why they were experiencing double the page load time of everyone else...
Things like this certainly tend to give one pause when implementing pages that change the backend state. A lot of people put sequence numbers in hidden form elements so the backend can detect a double-submit.
The causes I've seen before:
Missing stylesheet or image
Web developer addon for Chrome/Firefox sometimes requests things twice if you're validating HTML etc.
Browser inconsistency
Sometimes it's just too difficult to track down the root cause of a double request.
Either way, you should NOT be changing database state (or session state) through a GET request. The only SQL query you should be running without postdata is SELECT. All updates and inserts should be done using forms, even if the form consists only of a submit button.
src="" in certain elements on certain browsers (such as <img src="" />) can request the current page again.
404's are a prime source for a request seemingly being requested twice. Check your CSS, JS and image sources are all correct.
We had a very strange behaviour in our CMS where an iframe in a jQuery dialog lightbox made a doubled database insert.
After hours of debugging and loud WTFs we nailed it down. the dialog close method was setting the focus to the iframe of the dialog before destroying it and caused a reload of the iframe url!
I have seen this countless times. The internet is full of strange people who keep double-clicking on everything they come across.
You can stop this in you web site by attaching a global double-click event listener to every anchor tag ( tags).
For example, if you have jQuery installed, you can do the following:
jQuery('a').on('dblclick', function(e) { e.preventDefault(); });
This is just an example of course. You can achieve the same result using vanilla Javascript.
That should silently ignore the double click action.
In case they are fast clicking twice instead of double clicking, then you can use can throttle the click handle on all the links in the page to ensure that they cannot be clicked more than once within say ... 3 seconds.
Can I Stop or interrupt PHP script for particular time?
I would like to implement logic like below:
on mydomain.com/index.php there will be flash appear showing some intro of a product for suppose 20 sec. Once it complete, on same index.php page the home page of site will appear.
I am not aware about flash (action script).
Is it possible in PHP or Javascript ?
Usually "splash pages", as the're called, are made up of a seperate page.
In flash you can use the following code (Actionscript 3). Put it int the last frame, or use an event listener to redirecrect when the file is finished. The actual redirect looks like this:
getURL("http://www.woursecondpagehere.com", "_self")
Where you place it is up to you.
EDIT: I think that this is a reliable solution because this guarantees (if implemented correctly) that the page won't move until Flash is done. CSS and Javascript will work fine too.
There isn't a need to interrupt PHP in the scenario given. Though I think what you want is to load the rest of the HTML after a certain event occurs.
If thats the case then you can use AJAX to load the additional HTML from the server. Or you can use CSS to hide that content and show it after a certain point.
The META Refresh tag is probably not what you want since it will redirect the user after 20 seconds, regardless of how long it took to load your Flash file, then play it. Since the speed of the user's connection cannot be reliably predicted, you will probably end up with a poor user experience.
What you want to do is definitely possible but it will involve some interaction between the Flash object and the rest of your page. If you could do as Moshe suggested and simply have the Flash object redirect the user's browser to your actual home page with content on it, that would be easier.
If you insist on keeping everything on the same page, one way to do it is to call a Javascript function from the Flash object once it's finished playing. The function you call should be written to hide the Flash object and/or it's container and display the container () with all of your content that you're ready to show.
See this Codefidelity blog post for a quick tutorial on how to call JS functions from Flash.
Also, to clarify, you won't be interrupting or changing when your PHP script runs. That runs on the server before the page is created and sent back to the user's browser. All you need to do is structure the HTML/CSS of your page to have two DIVs: one with the Flash object in it and the other with all your normal page content. However, set the CSS to only show the DIV with the Flash object, then finally use Javascript to hide that DIV and show the one with the content in it.
Try this,
write the your flash (splash screen) <embede> code in index.html and simply use javascript redirect function with javascript timer functions to redirect to index.php where you actual content is there.
something like...
window.location = "http://your.domain.name/index.php"
or
location.href = "http://your.domain.name/index.php"
use setTimeout() to call redirect after specified time.