In JQtouch, any link is automatically convert into ajax call. I want to detect the moment the ajax call was send. This is so that i could insert a loading screen to let users know that the system is processing the submission.
I search through jqTouch API and apparently they only have callback events for page animation. Am i missing out on anything?
You can use the core jQuery global AJAX functions, for example $.ajaxStart() for the start of a batch of requests, or $.ajaxSend() to detect the beginning of each request. Something like this:
$(document).ajaxSend(function() {
alert("Request sending...");
});
Ready up on jQuery's Ajax Events: http://docs.jquery.com/Ajax_Events .
You may bind these to elements as follows:
$("...").bind("ajaxSend",myFunction) ;
every element specified this way will then react to a Ajax call being made with the specified callback function.
Related
I want to create a page with will be filled with dynamic info using Ajax (JQuery). The info will come from various GETs I need to do in other URLs.
I'll be using Sinatra + JQuery to to that, but as my WEB experience is almost null and don't have any idea how do to it right.
The requisites for this are:
Each time a GET completes, a new line of information should appear on the page.
If the GET could not be complete, a default info appear on the page.
My idea so far is to do something like this:
Have my controller performing each GET inside a thread.
Each time a thread ends, with success or not, I inform the view of the result and render a partial
I'll have as many partial as I need (for each GET I must do)
The first time I load the page I fill in the default info, them I update via AJAX with the successful GET responses
This does not seem the correct approach, so I'm asking someone that already did something similar or has more experience on this some help.
You start off with a simple get('/'){} route that holds the default message (or any other GET route). Then you have your other GET routes that you want to display on your default route. In Sinatra you can check whether a request is an xhr-request or not with a request.xhr? If you have an xhr request you return a json value to your view, otherwise reject the request or render a view with proper html. This is on your sinatra backend. In your views you can use JQuery or any other JS library or plain JS to handle asynchronous data requests. You can use the ajax function in JQuery to request data from your routes and then add them to your DOM. It's as simple as that :)
Now you will have to investigate on the JQuery site how to make ajax requests and how to append data to existing DOMs. That's all there is to it.
i have a web page that once it loads, it sends a lot of Ajax calls to fill some parts of the page. It's a Django template, it's sending around six calls with code similar to this :
$.get("http://127.0.0.1:8000/purchase/?name="+me.username, function(data){
$("#purchase").append(data);
});
sometimes they are called when the user clicks on a button, but they are mostly called when the page is refreshed.
Im new to Ajax, and I want to know if it's the right way to use this technology in an optimal manner. Is it alright to send Ajax calls similar calls that are separate ?
Thanks
For now i think just put those $.get() scripts into a jQuery ready function if you want them to fire when page loads and not on refresh... And yes its normal for a page to behave like this. That's what AJAX is meant for.
$(document).ready(function(){
$.get("http://127.0.0.1:8000/purchase/?name="+me.username, function(data){
$("#purchase").append(data);
});
//other $.get 's
});
Also use the jQuery ready() documentation.
I have an app that has several different types of form elements which all post data to the server with jQuery AJAX.
What I want to do is:
Show a loader during AJAX transmission
Prevent the user from submitting twice+ (clicking a lot)
This is easy to do on a one off basis for every type of form on the site (comments, file upload, etc). But I'm curious to learn if that is a more global way to handle this?
Something that's smart enough to say:
If a form is submitting to the server and waiting for a response, ignore all submits
Show a DISABLED class on the submitted / clicked item
Show a loading class on the class="spinner" which is closest to the submit item clicked
What do you think? Good idea? Done before?
Take a look at the jQuery Global Ajax Event Handlers.
In a nutshell, you can set events which occur on each and every AJAX request, hence the name Global Event Handlers. There are a few different events, I'll use ajaxStart() and ajaxComplete() in my code sample below.
The idea is that we show the loading, disable the form & button on the ajaxStart() event, then reenable the form and hide the loading element inside the ajaxComplete() event.
var $form = $("form");
$form.ajaxStart(function() {
// show loading
$("#loading", this).show();
// Add class of disabled to form element
$(this).addClass("disabled");
// Disable button
$("input[type=submit]", this).attr("disabled", true);
});
And the AJAX complete event
$form.ajaxComplete(function() {
// hide loading
$("#loading", this).hide();
// Remove disabled class
$(this).removeClass("disabled");
// Re-enable button
$("input[type=submit]", this).removeAttr("disabled");
});
You might need to attach to the ajaxError event as well in case an AJAX call fails since you might need to clean up some of the elements. Test it out and see what happens on a failed AJAX request.
P.S. If you're calling $.ajax or similar ($.getJSON), you can still set these events via $.ajaxStart and $.ajaxComplete since the AJAX isn't attached to any element. You'll need to rearrange the code a little though since you won't have access to $(this).
I believe you have to do 2 for sure and 3 to improve usability of your app. It is better to keep backend dumb but if you have a security issue you should handle that too.
I've been playing around with subscribing elements to AJAX events in jQuery.
I have an element that I am using to load AJAX response's. This element is only displayed IF there is data pertinent to the current context of the program.
So, I thought it would be nice and easy to .show() whenever an AJAX request has completed on it and hide it when I need to. I would like to remove the need to implicitly .show() the element every time I make an AJAX request.
In jQuery there is .ajaxSuccess() and .ajaxComplete(). These however, will fire when any AJAX request completes/succeeds, so when loading data in other parts of the page, my hidden element will .show().
The solution seems to be (per. the jQuery API reference) to use the ajaxOptions parameter in your event handler function:
$('.log').ajaxComplete(function(e, xhr, settings) {
if (settings.url == 'ajax/test.html') {
$(this).text('Triggered ajaxComplete handler.');
}
});
What I don't understand is the reason for registering an event handler for all AJAX requests to a specific element, besides being able to use $(this). Am I missing something, can I register an event handler for an AJAX request specific to an element?
If not, is there any event driven alternative to using the .url? The reason I ask is that I use the page fragment extensively for tracking page state and it would be easier to have an event handler .show() my element whenever an AJAX request loads data into it.
EDIT: Post title grammar.
My thinking, is that you want something like this:
$(document).ajaxComplete(function(e, xhr, settings) {
if(settings.url == 'ajax/test.html') {
$('#foo').text('Triggered ajaxComplete handler.');
} else if(settings.url == 'ajax/another.html') {
$('#bar').text('Triggered ajaxComplete handler.');
}
});
Does that make sense, or am I completely missing the point?
Bind a global event handler to AJAX requests and then use the event target member to decide to show elements:
$(document).ajaxSuccess(function (event, xhr, settings) {
if ($(event.target).is('#main'))
$('#main').show();
});
Would be nice to be able to fire on AJAX requests that only target specific elements, but there doesn't seem to be a way.
EDIT: Syntax
After I load a page through a WebBrowser, and I click a link that fires an AJAX script, I need to detect when the AJAX java script finishes loading HTML changes into a div. Since no DocumentCompleted event is fired when the AJAX script is run, I don't know when it finish running. Is there a way I can attach an event to be raised after I know 100% that the javascript finished changing the div?
The project is in C#.
Thanks
I did something similar recently (using jQuery):
$('#mydiv').change(function(){
// do stuff
}
);
Granted, I also use jQuery to set the HTML of that div. I suppose one non-jQuery approach for you could be to set HTML through your own function, which in turn can fire an onchange event.
#New in town: From my experience that is not correct. I use this on multiple DIVs that never get focus in the first place, and it works well and consistently. The normal behavior is as you describe, and normally only applies to the INPUT and SELECT elements, but this is not the case with jQuery.
There is no event. You must patch the JavaScript callback that the browser runs when the reply for the AJAX request comes in. This will contains code like "div.innerHTML = ...". Just put your code below that.