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What is AJAX best practice?

I am trying to learn javascript best practices and I am a bit confused. I have red that best ajax practice is:
function doSomething(arg1, arg2) {
jQuery.ajax({
var urlink = resourceURL
url: urlink,
cache: false,
data : "testData"+arg1,
type: "POST"
}).done(function(data) {
var obj = jQuery.parseJSON(data);
updateHtml1(obj);
updateHtml2(obj);
});
}
and not this way:
function getSomething(arg1, arg2) {
jQuery.ajax({
var urlink = resourceURL
url: urlink,
cache: false,
data : "testData"+arg1,
type: "POST",
success: function(data) {
var obj = jQuery.parseJSON(data);
updateHtml1(obj);
updateHtml2(obj);
}
});
}
I am asking which practice is best and why?

Either way is fine, it's just a difference in using the success callback or a promise, and in this case there is no difference. If you would want to return the result from the function doSomething then you would use the first method so that you can return the promise, as the done method then can be bound outside the function.
Both examples are overly complicated, and the var urlink = resourceURL is placed inside an object literal, so neither would actually work. You should also specify the dataType in the call, then the data will be parsed automatically.
In the first example you don't need an extra function wrapper.
function doSomething(arg1, arg2) {
jQuery.ajax({
url: resourceURL,
cache: false,
data : "testData"+arg1,
type: "POST",
dataType: "json"
}).done(function(data) {
updateHtml1(data);
updateHtml2(data);
});
}
And the second should be:
function getSomething(arg1, arg2) {
jQuery.ajax({
url: resourceURL,
cache: false,
data : "testData"+arg1,
type: "POST",
dataType: "json",
success: function(data) {
updateHtml1(data);
updateHtml2(data);
}
});
}

jQuery .ajax call never calling method

In this SO post I learned how to get a return value from an AJAX call:
function CallIsDataReady(input) {
$.ajax({
url: "http://www.blah.com/services/TestsService.svc/IsDataReady",
type: "GET",
contentType: "application/json; charset=utf-8",
data: input,
dataType: "json",
success: function (data) {
if (!data) {
setTimeout(function (inputInner) { CallIsDataReady(inputInner); }, 1000);
}
else {
//Continue as data is ready
callUpdateGrid(input);
}
}
});
}
$(document).ready(function () {
var input = { requestGUID: "<%=guid %>" };
CallIsDataReady(input);
});
This function calls its web service wich does return true. The problem is that inside the following callUpdateGrid, the logging shows that that web service method is not getting called from the $.ajax call:
function callUpdateGrid(input) {
console.log(input);
$.ajax({
url: "http://www.blah.com/services/TestsService.svc/GetContactsDataAndCountbyGUID",
type: "GET",
contentType: "application/json; charset=utf-8",
data: input,
dataType: "json",
success: function (data) {
var mtv = $find("<%= RadGrid1.ClientID %>").get_masterTableView();
console.log(data);
mtv.set_dataSource(data.d.Data);
mtv.dataBind();
}
});
}
Anyone know what is wrong?

It is always a good idea to include an error handler function as one of the options passed to $.ajax. For example, add this code after your success functions:
,
error: function(jqXHR, textStatus, errThrown) {
console.log("AJAX call failed");
console.log(errThrown);
}
That will log at least a bit of information if the $.ajax call doesn't succeed.
EDIT
According to your comment, this logs
SyntaxError: Invalid character
And in fact, I now see that you are giving a plain JavaScript object as the data option passed to $.ajax, but indicating that it is a JSON object in the dataType field. You need to actually convert the input object into JSON yourself, like so:
data: JSON.stringify(input),
dataType: 'json',
Alternatively, you could simply format input as a JSON object in first place, like so:
var input = { "requestGUID": "<%=guid %>" };
The quotes around the field name requestGUID are sufficient, in this case, to give you a JSON object.

Get parameter from JSON

In data from server I get the following JSON:
{
"response": {
"upload_url": "http:\/\/cs9458.vk.com\/upload.php?act=do_add&mid=6299927&aid=-14&gid=0&hash=73e525a1e2f4e6a0f5fb4c171d0fa3e5&rhash=bb38f2754c32af9252326317491a2c31&swfupload=1&api=1&wallphoto=1",
"aid": -14,
"mid": 6299927
}
}
I need to get upload_url. I'm doing:
function (data) {
var arrg = JSON.parse(data);
alert(data.upload_url);
});
but it doesn't work (alert doesn't show).
How do I get parameter upload_url?

It looks like you need to access arrg, not data. Also you need to access the 'response' key first.
function (data) {
var arrg = JSON.parse(data);
alert( arrg.response.upload_url);
}

There are several correct answers here, but there is one trigger that decides how you should handle your returned data.
When you use an ajax request and use JSON data format, you can handle the data in two ways.
treat your data as JSON when it returns
configure your ajax call for JSON by adding a dataType
See the following examples:
returned data string:
{"color1":"green","color2":"red","color3":"blue"}
ajax call without dataType:
$.ajax({
method: "post",
url: "ajax.php",
data: data,
success: function (response) {
var data = JSON.parse(response);
console.log(data.color1); // renders green
// do stuff
}
});
ajax call with dataType:
$.ajax({
method: "post",
url: "ajax.php",
dataType: "json", // added dataType
data: data,
success: function (response) {
console.log(response.color1); // renders green
// do stuff
}
});
In your case you probably used JSON.parse() when the call was already configured for JSON. Hope this makes things clear.

If response is in json and not a string then
alert(response.id);
or
alert(response['id']);
otherwise
var response = JSON.parse('{"id":"2231f87c-a62c-4c2c-8f5d-b76d11942301"}');
response.id ; //# => 2231f87c-a62c-4c2c-8f5d-b76d11942301

Your code has a small error. try:
function (data) {
var arrg = JSON.parse(data);
alert(arrg.response.upload_url);
});

jquery not properly serializing json in ajax call

Let me start by saying I am not extremely familiar with Javascript and I cannot figure out what is going on here.
I have the following function:
self.search = function () {
var searchTerms = {
"City": this.cityName,
"State": this.stateName,
"StoreNumber": this.storeNumber,
};
$.ajax("/api/SearchApi", {
data: searchTerms,
type: "POST", contentType: "application/json",
success: function (result) {
alert(result);
}
}
});
When I submit, what happens is that instead of submitting a nice JSON object as expected, it submits a JSON objected formatted as so: "City=testing&State=AL&StoreNumber=test "
Ideally I would like to use a GET method that passes the object to my server so that I can return the results, but when I use a get method, it simply appends the above to the API call url resulting in a URL request formed as so: http://localhost:57175/api/SearchApi?City=testing&State=AL&StoreNumber=test
Any help would be appreciated.

Make sure you add the dataType of JSON to your $.ajax({ }); object. That should solve the problem!
$.ajax({
// ...
data : JSON.stringify( searchTerms ), // Encode it properly like so
dataType : "json",
// ...
});

2 Things
Add the json content type(not the data type) to your ajax object important to note is the charset your server is using in this case utf-8.
Use the Json2 Library to stringify and parse Json when sending and retrieving it can be found here : https://github.com/douglascrockford/JSON-js/blob/master/json2.js
$.ajax({
url: URL,
type: "POST",
//Stringify the data you send to make shure its properly encoded
data: JSON.stringify(DATA),
//This is the type for the data that gets sent
contentType: 'application/json; charset=utf-8',
//This is for the data you receive
dataType: "json"
}).done(function(data) {
var dataYouGet = JSON.parse(data);
}).fail(function(xhr, ajaxOptions, thrownError) {
}).always(function(data) {
});

javascript jquery and using eval

i am currenty using jquery plugin to read a data file (data.html)
data.html has below format
[10,20,30,40,50]
my jquery data request and the javascript to return values is below
function test(){
var result=$.ajax({
url:'data.html',
type:'get',
dataType:'text',
async:false,
cache:false
}).responseText
return result;};
var my=test();
alert(my[0])
i want to get these values in the array format i.e i want my[0] to be value 10, but instead i get "[".
If i use eval function
my=eval(test());
i can get 10, but is there any other better way to store the returned ajax calls into an array instead of string?
Thanks
i tried the below answer and i am bit puzzled, the follow code results in myArray is null (in firebug), but i put async:false then it works. why do i need async:false to store the values into array ? (http://stackoverflow.com/questions/133310/how-can-i-get-jquery-to-perform-a-synchronous-rather-than-asynchronous-ajax-req)
jQuery.extend({getValues: function(url) {
var result = null;
$.ajax({
url: url,
type: 'get',
dataType: 'json',
cache: false,
success: function(data) {result = data;}
});
return result;}});
myArray=$.getValues("data.html");
alert(myArray[1]);

You don't need eval. Just indicate the proper dataType: 'json':
function test() {
return $.ajax({
url: 'data.html',
type: 'get',
dataType: 'json',
async: false,
cache: false
}).responseText;
}
var my = test();
alert(my[0]);
or even better do it asynchronously:
function test() {
$.ajax({
url: 'data.html',
type: 'get',
dataType: 'json',
cache: false,
success: function(result) {
alert(result[0]);
}
});
}
test();

I think jquery $.getScript('data.html',function(){alert("success"+$(this).text())} might be simpler. I have not had time to try it so if I'm on right track, improve this answer, if not I'm happy to learn now...