Hi I make randomly calling multiple ajax calls.how i can check all ajax calls are completed and values get loaded in combox and multiple boxes,PLease give any solution other than ajax status,Any javascript event which triggers when all elements loaded???,I tried prototype document.observe("dom:loaded", function() but its not working for ajax calls
how i can check all ajax calls are completed and values get loaded in combox and multiple boxes,PLease give any solution other than ajax status
Why? What's wrong with using the AJAX request status, which is the canonical way to determine the status of the request (and thus success or failure)?
There might be a legitimate reason for this restriction (though at first glance it appears not), but if so then it's because you're doing something unusual, such as making requests that you expect to "fail". If this is the case, then you'd need to make clear exactly what the constraints are anyway.
Failing that, just check the status and ensure that the remote server is returning the right status for requests (if it's under your control).
Related
I would like to have "Loading.." / "In Progress.." message during regular http request. This should be shown only during the http request cycle, and once you get the request is completed and you get the response, it should go off. I am keen about regular HTTP Request, and HTTP Request that take longer time and not AJAX. Code blocks, examples, pointers appreciated. Here is one approach, I would like to have common approach, so that it can be used for any http request.
You should use beforeSend and complete events:
$.ajax({
...
beforeSend: function(){
//Here you loading SHOW
},
complete: function(){
//Here you loading HIDE
}
...
});
Basically when executing a normal HTTP request (not AJAX), the client browser already provides a progress indicator. This indicator will vary between browsers and platforms and you cannot rely act on it.
Your javascript stops working once you navigate away from the page so don't look for a javascript solution to show such progress indicator. Depending on how this HTTP request is triggered there might be different ways to achieve that. For example if you have an anchor tag in your markup that triggers a normal HTTP request, you could subscribe to the click handler of this anchor and show an animated spinner using javascript and then let the browser do the redirect.
And as far as AJAX requests are concerned you could subscribe to the .ajaxStart() and .ajaxComplete() global handlers to respectively show and hide some spinner.
Of course everything will depend on the implementation. There's no magic solution that will handle all the possible cases. So basically you will have to find a solution that's adapted to your specific context which unfortunately you haven't detailed.
You could have an element on the page that gets hidden once the page has been fully loaded. E.g.:
<img id="loading" src="loading.gif" alt="Loading..." />
<script type="text/javascript">
$(function() {
$('img#loading').hide(); // Called when whole page has been loaded
});
</script>
I think it is not possible to render any information during pure javascript HTTPRequest synchronous call (not the case in JQuery). If you change a style, class.. just before calling the send method, this info will not be rendered.
To fix this issue, I changed call to asynchronous call, then the style, class .. changes can be rendered before the call returns (using onreadystatechange to get the result and reset style)
How i can make several requests to a server all at the same time, but preventing the mix of the responses?
Each of the ajax requests is made separately and you should set them up so that they go to different handlers when the ajax request is finished. The handlers may not be called in the same order since each may take longer than another.
If your code requires that they come back in the same order, you should create a single call that returns all the values you need. Or you need to queue the responses until they have all been processed
I have a web page and I am associating a note with the page storing it in my database, so that the whenever the next time the page is loaded that notice can been seen till it is deleted by some other user authorized to do the same. However, say I associate a note with the page after some content is loaded through AJAX. I want the note to appear only after that particular content has loaded next time on the web page. I would like to track the AJAX request and attach the note to it? I want to do it all through simple JavaScript code put at the bottom of any web page. How can it be done?
jQuery ajax provides methods to fire events before, during and after the ajax request. Please check the api here for complete list.
Here are couple of methods that are called after completion of every ajax request.
jQuery.ajaxComplete() - Register a handler to be called when Ajax requests complete.
jQuery.ajaxSuccess() - Show a message when an Ajax request completes successfully
These functions allows you to pass a callback function to trigger after event occurs. In that call back function check if content you want is loaded or not, then show the note.
Sample code for the above methods can be found here:
http://api.jquery.com/ajaxComplete/
http://api.jquery.com/category/ajax/
Hope this helps.
You'd need to write a wrapper for all of your ajax calls that checks the result and sees if it should add a note. Here's an example, assuming you're using jQuery to handle the ajax requests:
function ajaxWrapper(settings){
var old_callback = settings.complete;
settings.complete = function(request, status){
if(status == "200"){
// check the request.responseText and add your note if appropriate
}
if(old_callback){
old_callback(request, status);
}
}
jQuery.ajax(settings);
}
And then instead of calling jQuery.ajax() directly, call ajaxWrapper() instead.
An alternate option would be to include the note in your ajax response.
Is it possible to kill a previous ajax request?
We have tabular data very adjacent to each other. On mouseover event of each data we are making a request to our server using JQuery Ajax object and showing in popup.
But as frequently we move mouse to other tabular contents previous Ajax responses are being displayed inside popups prior exact response being displayed which is meant for that tabular content.
I need when new Ajax request is generated previous request/response should be killed, so that always expected latest response is available inside popup.
I am using JQuery, PHP and Mysql to server the request.
Could you create a custom Javascript Sync object which would be shared by the function making subsequent ajax calls?
Assign a sequentially generated id as a parameter to the request call going in. Include the same id in response. On firing every request assign a new id, incremented by 1 or whatever logic. If the current id in response is not same as the one in shared object; ignore the response else render the response.
this would cleanly solve the race condition. I am not sure myself if there is a way to kill the request prematurely but it would at least not create rendering problem that you face now.
Another option would be not to initiate another request until the first is completed.
Yes and no. That is the point of Ajax. To be able to do something asynchronously. What you are wanting to do is to abort a request which destroys the idea of asynchronously. Perhaps what you can do is, if you send another request, set a value somewhere indicating the number of requests, then in the callbacks to your requests, check if the amount of request is higher than 1, if so ignore the response.
Check this AJAX Manager plugin. The XmlHttpRequest has an abort() function but jQuery doesn't have a wrapper for it.
I'm just wondering..is it possible to receive multiple responses from a single ajax call?
I'm thinking purely for aesthetic purposes to update the status on the client side.
I have a single ajax method that's called on form submit
$.ajax({
url: 'ajax-process.php',
data: data,
dataType: 'json',
type: 'post',
success: function (j) {
}
});
I can only get one response from the server-side. Is it possible to retrieve intermittent statuses? Such as:
Default (first): Creating account
Next: Sending email confirmation
Next: Done
Thanks for your help! :)
From a single ajax call, I don't think it is possible.
What you could do is check frequently where the process is (it's what is used for the upload bars in gmail for example). You do a first ajax request to launch the process, and then a series of ajax request to ask the server how he is doing. When the server answers "I'm done", you're good to go, and until that you can make the server respond and say the current state.
There is something called comet which you can set up to "push" requests to client, however it is probably way more than what you are wanting to invest in, time-wise.
You can open up a steady stream from the server, so that it continues to output, however I'm not sure how client-side script can handle these as individual "messages". Think about it like a server that outputs some info to the browser, does more work, outputs some more to the browser, does more work, etc. This shows up more or less in real time to the browser as printed text. It is one long response, but it is still one response. I think ajax only handles a response once it finished being sent, but maybe someone else will know more than me on the topic.
But you couldn't have the server output several individual responses without reloading itself, at least not with PHP, because once you start outputting the response, the response has begun and you can't chop that up without finishing the response, which happens when the script is done executing.
Your best bet is with the steady stream, but again, I'm not sure how ajax handles getting responses in chunks.
Quick Update
Based on the notes for this plugin:
[http://plugins.jquery.com/project/ajax-http-stream]
things don't look promising. Specifically:
Apparently the trend is to disallow access to the xmlhttprequest.responseText before the request is complete (stupid imo). Sorry there's nothing I can do to fix this
Thus, not only can you not get what you want in one request, you probably can't get it multiple requests, unless you want to break up the actual server-side process into several parts, and only have it continue to the next step when an ajax function triggers it.
Another option would be to have your script write it's status at specific points to another file on the server, call it "status.xml" or "status.txt". Have your first ajax function initialize the process, and have a second ajax function that queries this status file and outputs that to the user.
It is possible, but it has more to do with your backend script. As Anthony mentioned there is a tech called comet. Another term I've heard is called "Long polling". The idea is that you delay the time in which your php(insert language of choice) script finished processing.
In php you can do something like this:
while($response !== 'I'm done'){
sleep(1);
}else{
return $some_value;
exit();
}
This code stops your script from completely finishing. sleep(1) allows the script to stop and lets the server rest for 1 millisecond, before it loops back through. You can adjust the sleep time based on your needs. In php the amount of time the script sleeps is not counted agains your server timeout time.
You'll obviously need to make more checks for you code. You'll probably also want to allow for an abort script call. Something like sending a get request to kill the backend script. Maybe on the javascript unload event.
In the tests that I've done. I made the initial ajax call, and when the value was returned, I made another ajax call, that way your back end script wont time out.
I've only played around with this on my local server, so i'm not sure how real world this is, but it works.