How to execute JavaScript after dropdown data is inserted via Ajax? - javascript

I have a form that loads some of its Data dynamically via Ajax, where, apart of a lot of other stuff, I fill a dropdown list. When selecting an item it will load the corresponding data into a table.
That all works fine, but now I want to be able to, by default, load the data of the first element once the page loads.
But since the dropdown populates over Ajax, it is filled slightly after $(document).ready(), so that doesn't work.
One way it might work would be to just wait for a second or two, since then it should all be loaded, but that really isn't something I fancy doing.
Any idea how I could achieve that?
I already tried it with onloadeddata="loadData($(this)[0].selectedOptions[0].value)" on the select tag, but that doesn't seem to do anything.
EDIT:
And I don't want to execute this in the ajax success function as data might also be loaded in other ways. It should really be the dropdown field or something that watches the dropdown, that executes this.

JQuery Ajax provides a callback for successful request.
$.ajax({
url : 'stackoverflow.com/api',
type: 'GET',
success : successMethod
})
function successMethod(){
// foo
}
Once the request receives a response successMethod will be called.

jquery ajax have a success function in which you can do such kind of functionality. To do so you can try:
success: function(response) {
// fill the form value with 'response'
$('#dropdown_id').val('any_value'); // this will set the dropdown to specific value
}

$.ajax({
url: "test.html",
...
}).done(function(data) {
// do something with your data in here
});

Related

How do I send data to my ajax method from my controller?

I want to update a element based on things that are happening in the code server side.
For instance, when I invoke my "Start" function by clicking a button on my page it should change the text inside the element to "Downloading", and then once it's done it should change the text to "Done".
I have this script on my page which invokes a action and updates the text after making a successful request.
<script>
function StartDownload() {
$.ajax({
url: '#Url.Action("Start", "MyPage")', success: function (result) {
$("#badge").removeClass("badge-danger").addClass("badge-info").html("Downloading");
}});
};
</script>
as you can see, right now it's just making a request and on success it changes the class and it changes the text to "Downloading".
The goal is to change it to "Downloading" once it invokes the method, and then once the method finishes I want to change the text to "Done".
And I'm not sure how to do that, I need to some how listen for multiple calls in my ajax method but I have no idea how to do that.
What's the proper way of achieving this?
I was thinking of doing something like this but I'm not sure if that's valid
public ActionResult Start()
{
//Post data back to the ajax to tell it to change to "Downloading"
StartDownload();
//Post data back to the ajax to tell it to change to "Finished"
return View();
}
It is pretty simple in fact.
Except success $.ajax() has a lot of other "events", which you can use.
beforeSend for example may be your choice, because it executes just before ajax call
You can find more events here:
https://api.jquery.com/jquery.ajax/

jQuery AJAX inside another AJAX call. Sync and finished issues

I get a list of users with an AJAX call, but within the AJAX I call another AJAX to get some information that I could not get with the first AJAX call.
This is basically the structure I'm using, I've removed some unneccesary code that would just clutter, it is possible that there is some syntax errors here and there.
But the code basically works but there are some issues.
function doAJAX(){
$(".loading").show();
$("#table").hide();
$.ajax({
type: "POST",
url: "#Url.Action("Action", "Controller")",
data: { variable: varVariable},
dataType: "json",
success: function (data) {
$.each(data, function (index, value) {
$.ajax({
type: "POST",
url: "#Url.Action("Action", "Controller")",
data: { variable: value.id},
success: function (data2) {
$.each(data2, function (index2, value2) {
$("#tableBody").append("<tr><td>" + value.test +"</td><td>" + value2.test +"</td></tr>");
});
}
});
});
}
});
}
I hide my table at the start, when the AJAX is complete I want to show it again. Where exactly should I place it? Even if I place it at the end of the first AJAX success function it does not work because it gets executed while the other AJAX is still running.
For some reason my list ends up in an odd order everytime the AJAX runs, my list is sorted by alphabetical order yet with this AJAX it ends up random everytime, sometimes the user Adam is at the start, sometimes in the middle and so on. The list itself is fine and in correct order
I do a lot of mathematics that is probably slowing down the second AJAX call which is probably why it ends up in a weird order
Both of these issues are happening because the two AJAXs aren't running "together" but individually, is there a way to make them sync with each other and is there a good way to be sure that the AJAX is completed and now I can show my table?
Sending ajax request inside a loop doesn't seem like a good idea. Why won't you send one ajax request with array of id's as a data, inside your serverside script just get "WHERE id IN (id_list)" array of user records and return them as json-encoded object, and then output it inside a double loop, first for <tr>, second for a list of fields.
I'm sorry i can't provide code, as i don't know what is being returned from your requests to server.

Change value of dynamic inputs

I have a modal window that has a lot of new dynamic elements (inputs, buttons, etc.). I want to see if a certain element(or in this case, and input) gets created and if it does, then change its value.
The scenario is that if I make an ajax request for populating data, and as the user browses the modal window I can reuse some of that data. When the input field I'm looking for gets created, I can just put the value of the ajax call I made previously.
I have tried: $("#myinput_id").val(sellerData['id']);
obviously the above wont work because the element doesn't exists, yet. I'm also trying to avoid new ajax calls for the same data :/
Any thoughts?
$( "#add").bind('click', function() {
$.ajax({
url: '/seller/get',
type: 'POST',
success: function(response) {
sellerData = jQuery.parseJSON(response);
//other code here
//this doesn't work
$("#myinput_id").val(sellerData['id']);
}
});
});
Then the above gets triggers. The input field doesn't exist yet. How can I make it "look for it" if in the future the input field gets created?
Try using .length http://api.jquery.com/length/
if($("#myinput_id").length) //There is at least one element selected
//Do something
a bit confusing question you are saying u want to populate the data and your are using POST

how to run an onchange function when page is loaded if the selected box is already selected

Im running into a problem where i have an ajax driven page that is drawn when a user selects something from a simple drop down:
<select id = "selectdepartment">
<option id = "default">Select an option...</option>
....
</select>
and the remainder of the page is drawn using the jquery .change() :
$('#selectdepartment').change(function(){
});
Which then runs some ajax to php script. everything works great, the problem is when i submit a form that was drawn with ajax (using $_SERVER['PHP_SELF'];), the data gets submited, the page reloads, and the page is cleared but the select box is still left where it was. The user has to move to a different option then back to the one the selected originally to re-fire the .change(). that sucks.
I could fix this by passing a php variable in all of my forms, then checking to see the variable set on every page load and if it is draw the page parts then, but this would lead to pretty messy code and it's less than desirable.
There has to be a way to do this with the jquery library, though my knowledge of the javascript language in general is not what i would like it to be. If anyone has any helpful hints please share, dont do it for me though, i wont learn that way :)
edit: code with .trigger
$('#selectdepartment').change(function(){
var department = $('#selectdepartment').val();
var day = $('#data').data('day');
var month = $('#data').data('month');
var year = $('#data').data('year');
//alert (department);
if(department === "Select an option..."){
$('.hiddenuntildepartmentisselected').css({"display":"none"});
}
else{
$('.hiddenuntildepartmentisselected').css({"display":"block"});
}
showpoints(department);
drawpointstable(department, day, month, year);
displaytheuseresforselecteddepartment(department, '');
$('#sendthedepartment').val(''+department+'');
$('#hiddendepartmentidforaddinganewpoint').val(''+department+'');
}).trigger('change');//end run functions
You can use the .trigger() function to immediately trigger the change event handler when the page has loaded:
$('#selectdepartment').change(function() {
// code here
}).trigger('change');
Or if you need to call it elsewhere via JavaScript/jQuery:
$('#selectdepartment').trigger('change'); // or just .change() as a shorthand
Updated
Your button for the form could make use of the onClick attribute, which would invoke a method to parse the form fields and post the data to your php script via .ajax().
In the success event method you then check any flags you need to and modify the element as you desire if needed.
Basic example:
Inside of .ajax():
...
url: 'xxx.xxx.xxx',
async: true,
type: 'POST',
dataType: 'html',
data: JSON.stringify( form_fields ),
beforeSend: function()
{
// Pre send stuff, like starting a loading gif
},
success: function( data, textStatus, xhr )
{
// Be sure you load the page with the content first
$( '#containing-div' ).html( data );
// Do your check here, and modify your element if needed here
if( flagtocheck === 'xxx' )
{
// Modify the element in question...
}
// I call a custom method termed `.ctrls()` here that makes any
// adjustments to the DOM once its loaded/updated.
},
error: function( xhr, textStatus, errorThrown )
{
}
Of course, you'll want to set flagtocheck appropriately in your case.
Hope that helps!
Note regarding edit
This post was edited to be a little more descriptive and more easily understood. Since the person asking the question is already using the .ajax() method, the success event method is the ideal place for doing what the person asking the question is requesting. It is 1 less method invocation to directly modify the element there than using it to call .trigger() or .change() which then also directly modifies the element.

Any function with mixed functionality of .ajax() and .load()?

.ajax() can send a post request and get data in return where as .load() can get any element in the rendered page. How to create a form when submitted(asynchromously) instead of getting back some data should get the page element of the rendered page that would be generated had there been normal submission instead of ajax submission?
I dont want to write views(Django) for xhr, normal requests separately. So, When I submit a form by ajax I dont want to hijack default action but only want to get some element of the rendered post submission page instead of actually being redirected to that post submission page which would have happened hadn't it been an xhr request.
Update:
load will do a POST rather than a GET if you supply the data to send as an object rather than a string. From the docs:
Request Method
The POST method is used if data is provided as an object; otherwise, GET is assumed.
So:
$("#target").load("/path/to/resource selector_for_relevant_elements", {});
..should convert the load from GET to POST. Of course, you'd replace {} with the arguments you want to send.
Original answer:
You can do the POST directly with ajax and then process the returned HTML yourself. For instance, to turn this load:
$("#target").load("/path/to/resource selector_for_relevant_elements");
..into a POST:
$.ajax({
url: "/path/to/resource",
method: "POST",
dataType: "html",
success: function(html) {
// Build the elemnts of the result in a disconnected document
var page = $("<div>").append(html); // See note below
// Find the relevant elements and put them in target
$("#target").html(page.find("selector_for_relevant_elements"));
}
});
I've done the wrapper div because that's what jQuery's load function does. You may want to look at the source for load (that line number will rot, of course, but the filename is unlikely to change) to see if there are other tricks you need to replicate.

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