Jquery get fail error

jQuery.get()

jQuery.get( url [, data ] [, success ] [, dataType ] ) Returns: jqXHR

Description: Load data from the server using a HTTP GET request.

version added: 1.0 jQuery.get( url [, data ] [, success ] [, dataType ] )

version added: 1.12-and-2.2 jQuery.get( [settings ] )

This is a shorthand Ajax function, which is equivalent to:

The success callback function is passed the returned data, which will be an XML root element, text string, JavaScript file, or JSON object, depending on the MIME type of the response. It is also passed the text status of the response.

As of jQuery 1.5, the success callback function is also passed a «jqXHR» object (in jQuery 1.4, it was passed the XMLHttpRequest object). However, since JSONP and cross-domain GET requests do not use XHR , in those cases the jqXHR and textStatus parameters passed to the success callback are undefined.

Most implementations will specify a success handler:

This example fetches the requested HTML snippet and inserts it on the page.

The jqXHR Object

As of jQuery 1.5, all of jQuery’s Ajax methods return a superset of the XMLHTTPRequest object. This jQuery XHR object, or «jqXHR,» returned by $.get() implements the Promise interface, giving it all the properties, methods, and behavior of a Promise (see Deferred object for more information). The jqXHR.done() (for success), jqXHR.fail() (for error), and jqXHR.always() (for completion, whether success or error; added in jQuery 1.6) methods take a function argument that is called when the request terminates. For information about the arguments this function receives, see the jqXHR Object section of the $.ajax() documentation.

The Promise interface also allows jQuery’s Ajax methods, including $.get() , to chain multiple .done() , .fail() , and .always() callbacks on a single request, and even to assign these callbacks after the request may have completed. If the request is already complete, the callback is fired immediately.

Источник

jQuery.get()

jQuery.get( url [, data ] [, success ] [, dataType ] ) Returns: jqXHR

Description: Load data from the server using a HTTP GET request.

version added: 1.0 jQuery.get( url [, data ] [, success ] [, dataType ] )

version added: 1.12-and-2.2 jQuery.get( [settings ] )

This is a shorthand Ajax function, which is equivalent to:

The success callback function is passed the returned data, which will be an XML root element, text string, JavaScript file, or JSON object, depending on the MIME type of the response. It is also passed the text status of the response.

As of jQuery 1.5, the success callback function is also passed a «jqXHR» object (in jQuery 1.4, it was passed the XMLHttpRequest object). However, since JSONP and cross-domain GET requests do not use XHR , in those cases the jqXHR and textStatus parameters passed to the success callback are undefined.

Most implementations will specify a success handler:

This example fetches the requested HTML snippet and inserts it on the page.

The jqXHR Object

As of jQuery 1.5, all of jQuery’s Ajax methods return a superset of the XMLHTTPRequest object. This jQuery XHR object, or «jqXHR,» returned by $.get() implements the Promise interface, giving it all the properties, methods, and behavior of a Promise (see Deferred object for more information). The jqXHR.done() (for success), jqXHR.fail() (for error), and jqXHR.always() (for completion, whether success or error; added in jQuery 1.6) methods take a function argument that is called when the request terminates. For information about the arguments this function receives, see the jqXHR Object section of the $.ajax() documentation.

The Promise interface also allows jQuery’s Ajax methods, including $.get() , to chain multiple .done() , .fail() , and .always() callbacks on a single request, and even to assign these callbacks after the request may have completed. If the request is already complete, the callback is fired immediately.

Источник

jQuery.ajax()

jQuery.ajax( url [, settings ] ) Returns: jqXHR

Description: Perform an asynchronous HTTP (Ajax) request.

version added: 1.5 jQuery.ajax( url [, settings ] )

version added: 1.0 jQuery.ajax( [settings ] )

Data to be sent to the server. If the HTTP method is one that cannot have an entity body, such as GET, the data is appended to the URL.

When data is an object, jQuery generates the data string from the object’s key/value pairs unless the processData option is set to false . For example, < a: «bc», d: «e,f» >is converted to the string «a=bc&d=e%2Cf» . If the value is an array, jQuery serializes multiple values with same key based on the value of the traditional setting (described below). For example, < a: [1,2] >becomes the string «a%5B%5D=1&a%5B%5D=2» with the default traditional: false setting.

When data is passed as a string it should already be encoded using the correct encoding for contentType , which by default is application/x-www-form-urlencoded .

In requests with dataType: «json» or dataType: «jsonp» , if the string contains a double question mark ( ?? ) anywhere in the URL or a single question mark ( ? ) in the query string, it is replaced with a value generated by jQuery that is unique for each copy of the library on the page (e.g. jQuery21406515378922229067_1479880736745 ).

An object of numeric HTTP codes and functions to be called when the response has the corresponding code. For example, the following will alert when the response status is a 404:

If the request is successful, the status code functions take the same parameters as the success callback; if it results in an error (including 3xx redirect), they take the same parameters as the error callback.

In jQuery 1.5, the withCredentials property was not propagated to the native XHR and thus CORS requests requiring it would ignore this flag. For this reason, we recommend using jQuery 1.5.1+ should you require the use of it.

The $.ajax() function underlies all Ajax requests sent by jQuery. It is often unnecessary to directly call this function, as several higher-level alternatives like $.get() and .load() are available and are easier to use. If less common options are required, though, $.ajax() can be used more flexibly.

At its simplest, the $.ajax() function can be called with no arguments:

Note: Default settings can be set globally by using the $.ajaxSetup() function.

This example, using no options, loads the contents of the current page, but does nothing with the result. To use the result, you can implement one of the callback functions.

The jqXHR Object

The jQuery XMLHttpRequest (jqXHR) object returned by $.ajax() as of jQuery 1.5 is a superset of the browser’s native XMLHttpRequest object. For example, it contains responseText and responseXML properties, as well as a getResponseHeader() method. When the transport mechanism is something other than XMLHttpRequest (for example, a script tag for a JSONP request) the jqXHR object simulates native XHR functionality where possible.

As of jQuery 1.5.1, the jqXHR object also contains the overrideMimeType() method (it was available in jQuery 1.4.x, as well, but was temporarily removed in jQuery 1.5). The .overrideMimeType() method may be used in the beforeSend() callback function, for example, to modify the response content-type header:

The jqXHR objects returned by $.ajax() as of jQuery 1.5 implement the Promise interface, giving them all the properties, methods, and behavior of a Promise (see Deferred object for more information). These methods take one or more function arguments that are called when the $.ajax() request terminates. This allows you to assign multiple callbacks on a single request, and even to assign callbacks after the request may have completed. (If the request is already complete, the callback is fired immediately.) Available Promise methods of the jqXHR object include:

jqXHR.done(function( data, textStatus, jqXHR ) <>);

An alternative construct to the success callback option, refer to deferred.done() for implementation details.

jqXHR.fail(function( jqXHR, textStatus, errorThrown ) <>);

An alternative construct to the error callback option, the .fail() method replaces the deprecated .error() method. Refer to deferred.fail() for implementation details.

jqXHR.always(function( data|jqXHR, textStatus, jqXHR|errorThrown ) < >); (added in jQuery 1.6)

An alternative construct to the complete callback option, the .always() method replaces the deprecated .complete() method.

In response to a successful request, the function’s arguments are the same as those of .done() : data, textStatus, and the jqXHR object. For failed requests the arguments are the same as those of .fail() : the jqXHR object, textStatus, and errorThrown. Refer to deferred.always() for implementation details.

jqXHR.then(function( data, textStatus, jqXHR ) <>, function( jqXHR, textStatus, errorThrown ) <>);

Incorporates the functionality of the .done() and .fail() methods, allowing (as of jQuery 1.8) the underlying Promise to be manipulated. Refer to deferred.then() for implementation details.

Deprecation Notice: The jqXHR.success() , jqXHR.error() , and jqXHR.complete() callbacks are removed as of jQuery 3.0. You can use jqXHR.done() , jqXHR.fail() , and jqXHR.always() instead.

The this reference within all callbacks is the object in the context option passed to $.ajax in the settings; if context is not specified, this is a reference to the Ajax settings themselves.

For backward compatibility with XMLHttpRequest , a jqXHR object will expose the following properties and methods:

• readyState
• responseXML and/or responseText when the underlying request responded with xml and/or text, respectively
• status
• statusText (may be an empty string in HTTP/2)
• abort( [ statusText ] )
• getAllResponseHeaders() as a string
• getResponseHeader( name )
• overrideMimeType( mimeType )
• setRequestHeader( name, value ) which departs from the standard by replacing the old value with the new one rather than concatenating the new value to the old one
• statusCode( callbacksByStatusCode )

No onreadystatechange mechanism is provided, however, since done , fail , always , and statusCode cover all conceivable requirements.

Callback Function Queues

The beforeSend , error , dataFilter , success and complete options all accept callback functions that are invoked at the appropriate times.

As of jQuery 1.5, the fail and done , and, as of jQuery 1.6, always callback hooks are first-in, first-out managed queues, allowing for more than one callback for each hook. See Deferred object methods, which are implemented internally for these $.ajax() callback hooks.

The callback hooks provided by $.ajax() are as follows:

1. beforeSend callback option is invoked; it receives the jqXHR object and the settings object as parameters.
2. error callback option is invoked, if the request fails. It receives the jqXHR , a string indicating the error type, and an exception object if applicable. Some built-in errors will provide a string as the exception object: «abort», «timeout», «No Transport».
3. dataFilter callback option is invoked immediately upon successful receipt of response data. It receives the returned data and the value of dataType , and must return the (possibly altered) data to pass on to success .
4. success callback option is invoked, if the request succeeds. It receives the returned data, a string containing the success code, and the jqXHR object.
5. Promise callbacks — .done() , .fail() , .always() , and .then() — are invoked, in the order they are registered.
6. complete callback option fires, when the request finishes, whether in failure or success. It receives the jqXHR object, as well as a string containing the success or error code.

Data Types

Different types of response to $.ajax() call are subjected to different kinds of pre-processing before being passed to the success handler. The type of pre-processing depends by default upon the Content-Type of the response, but can be set explicitly using the dataType option. If the dataType option is provided, the Content-Type header of the response will be disregarded.

The available data types are text , html , xml , json , jsonp , and script .

If text or html is specified, no pre-processing occurs. The data is simply passed on to the success handler, and made available through the responseText property of the jqXHR object.

If xml is specified, the response is parsed using jQuery.parseXML before being passed, as an XMLDocument , to the success handler. The XML document is made available through the responseXML property of the jqXHR object.

If json is specified, the response is parsed using jQuery.parseJSON before being passed, as an object, to the success handler. The parsed JSON object is made available through the responseJSON property of the jqXHR object.

If script is specified, $.ajax() will execute the JavaScript that is received from the server before passing it on to the success handler as a string.

If jsonp is specified, $.ajax() will automatically append a query string parameter of (by default) callback=? to the URL. The jsonp and jsonpCallback properties of the settings passed to $.ajax() can be used to specify, respectively, the name of the query string parameter and the name of the JSONP callback function. The server should return valid JavaScript that passes the JSON response into the callback function. $.ajax() will execute the returned JavaScript, calling the JSONP callback function, before passing the JSON object contained in the response to the $.ajax() success handler.

For more information on JSONP, see the original post detailing its use.

Sending Data to the Server

By default, Ajax requests are sent using the GET HTTP method. If the POST method is required, the method can be specified by setting a value for the type option. This option affects how the contents of the data option are sent to the server. POST data will always be transmitted to the server using UTF-8 charset, per the W3C XMLHTTPRequest standard.

Advanced Options

The global option prevents handlers registered using .ajaxSend() , .ajaxError() , and similar methods from firing when this request would trigger them. This can be useful to, for example, suppress a loading indicator that was implemented with .ajaxSend() if the requests are frequent and brief. With cross-domain script and JSONP requests, the global option is automatically set to false . See the descriptions of these methods below for more details.

If the server performs HTTP authentication before providing a response, the user name and password pair can be sent via the username and password options.

Ajax requests are time-limited, so errors can be caught and handled to provide a better user experience. Request timeouts are usually either left at their default or set as a global default using $.ajaxSetup() rather than being overridden for specific requests with the timeout option.

By default, requests are always issued, but the browser may serve results out of its cache. To disallow use of the cached results, set cache to false . To cause the request to report failure if the asset has not been modified since the last request, set ifModified to true .

The scriptCharset allows the character set to be explicitly specified for requests that use a

Источник

This is a tutorial on how to handle errors when making Ajax requests via the jQuery library. A lot of developers seem to assume that their Ajax requests will always succeed. However, in certain cases, the request may fail and you will need to inform the user.

Here is some sample JavaScript code where I use the jQuery library to send an Ajax request to a PHP script that does not exist:

$.ajax({
     url: 'does-not-exist.php',
     success: function(returnData){
         var res = JSON.parse(returnData);
     },
     error: function(xhr, status, error){
         var errorMessage = xhr.status + ': ' + xhr.statusText
         alert('Error - ' + errorMessage);
     }
});

If you look at the code above, you will notice that I have two functions:

• success: The success function is called if the Ajax request is completed successfully. i.e. If the server returns a HTTP status of 200 OK. If our request fails because the server responded with an error, then the success function will not be executed.
• error: The error function is executed if the server responds with a HTTP error. In the example above, I am sending an Ajax request to a script that I know does not exist. If I run the code above, the error function will be executed and a JavaScript alert message will pop up and display information about the error.

The Ajax error function has three parameters:

• jqXHR
• textStatus
• errorThrown

In truth, the jqXHR object will give you all of the information that you need to know about the error that just occurred. This object will contain two important properties:

• status: This is the HTTP status code that the server returned. If you run the code above, you will see that this is 404. If an Internal Server Error occurs, then the status property will be 500.
• statusText: If the Ajax request fails, then this property will contain a textual representation of the error that just occurred. If the server encounters an error, then this will contain the text “Internal Server Error”.

Obviously, in most cases, you will not want to use an ugly JavaScript alert message. Instead, you would create an error message and display it above the Ajax form that the user is trying to submit.

JQuery 3.0: The error, success and complete callbacks are deprecated.

Update: As of JQuery 3.0, the success, error and complete callbacks have all been removed. As a result, you will have to use the done, fail and always callbacks instead.

An example of done and fail being used:

$.ajax("submit.php")
  .done(function(data) {
      //Ajax request was successful.
  })
  .fail(function(xhr, status, error) {
      //Ajax request failed.
      var errorMessage = xhr.status + ': ' + xhr.statusText
      alert('Error - ' + errorMessage);
})

Note that always is like complete, in the sense that it will always be called, regardless of whether the request was successful or not.

Hopefully, you found this tutorial to be useful.

The jQuery Get function is used to make AJAX calls and can be helpful to update a web page with partial page reloading. It uses HTTP GET method to initiate an AJAX request and fetch data from the external pages.

Let us understand all about this method in details.

Syntax of jQuery Get Method

jQuery.get( url [, data ] [, success ] [, dataType ] )

Parameters:

jQuery Get Method to Fetch Contents of a Text File

Let’s fetch a text file’s content with the jQuery Get method:

<button id="loadTextFile">Try</button>
<div id="textData"></div>
 
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script>
    $(document).ready(function () {
        $.get("file.txt", function (result, status, xhr) {
            $("#textData").html(result);
        });    
    });
</script>

The jQuery .get() method makes the AJAX call to the file.txt and shows it’s contents inside a div called textData.

Not just a text file, the above code can be use to fetch contents of other file types, like HTML, JSON, XML, etc.

Capturing jQuery Get Error

Use .fail() to capture any errors that come during the AJAX request.

See the below code:

<button id="loadNoTextFile">Try</button>
<div id="textNoData"></div>
 
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script>
    $(document).ready(function () {
        $("#loadNoTextFile").click(function (e) {
            $.get("no-file.txt", function (result, status, xhr) {
                $("#textNoData").html(result);
            }).fail(function (xhr, status, error) {
            $("#textNoData").html("Result: " + status + " " + error + " " + xhr.status + " " + xhr.statusText)
        });
    }); 
</script>

In the above code, when trying to access a non-existing file, the .fail() function is called and it shows the message – Result: error Not Found 404 Not Found.

jQuery Get method to Fetch Data from Database

With the jQuery Get method you can make AJAX calls to a server page also. This server page in turn fetches data from the Database and returns it back as an AJAX response.

Let us create a small demo application in ASP.NET Web Forms to understand this feature.

jQuery Get Demo Application

There are 2 pages – one is HTML and other is .ASPX. The HTML page has 3 controls – 2 selects and a button.

On clicking the button, the 2 ‘select’ control values are passed to the .ASPX page by the jQuery Get method.

The HTML page code:

<div id="message"></div>
<select id="sportSelect">
    <option value="Select">Select Sports</option>
    <option value="Tennis">Tennis</option>
    <option value="Football">Football</option>
    <option value="Cricket">Cricket</option>
</select>
<select id="playerSelect">
    <option value="Select">Select Sports Person</option>
    <option value="Maria Sharapova">Maria Sharapova</option>
    <option value="Cristiano Ronaldo">Cristiano Ronaldo</option>
    <option value="Sachin Tendulkar">Sachin Tendulkar</option>
</select>
 
<button id="loadDatabase">Try</button>
<div id="dbData"></div>

The jQuery Code:

<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.1.0/jquery.min.js"></script>
<script>
    $("#loadDatabase").click(function (e) {
        $.get("result.aspx",
            {
                sport: $("#sportSelect").val(),
                player: $("#playerSelect").val()
            },
            function (result, status, xhr) {
                $("#dbData").html(result);
            }).fail(function (xhr, status, error) {
                $("#dbData").html("Result: " + status + " " + error + " " + xhr.status + " " + xhr.statusText)
        });
    });
</script>

In the .ASPX page, I get these 2 select control values, using Request.QueryString method.

I then fetch the respective data from the database.

Once I have the data from the DB then I use the Response.Write method to send it to the jQuery Get method as AJAX response.

The .ASPX page code:

List<MyDataBase> myDataBase;
protected void Page_Load(object sender, EventArgs e)
{
    if (!IsPostBack)
    {
        LoadData();
        SearchDatabase();
    }
}
 
void SearchDatabase()
{
    string sport = Request.QueryString["sport"];
    string player = Request.QueryString["player"];
    try
    {
        string information = myDataBase.FirstOrDefault(x => x.sport == sport & x.player == player).information;
        Response.Write(information);
        Response.End();
    }
    catch (Exception ex)
    {
        Response.Write("NO DATA");
        Response.End();
    }
}
 
void LoadData()
{
    myDataBase = new List<MyDataBase>();
    myDataBase.Add(new MyDataBase() { sport = "Tennis", player = "Maria Sharapova", information = "Maria Sharapova is a...});
    myDataBase.Add(new MyDataBase() { sport = "Football", player = "Cristiano Ronaldo", information = "Cristiano Ronaldo is a..." });
    myDataBase.Add(new MyDataBase() { sport = "Cricket", player = "Sachin Tendulkar", information = "Sachin Tendulkar is a..." });
}
 
class MyDataBase
{
    public string sport { get; set; }
    public string player { get; set; }
    public string information { get; set; }
}

Instead of a Database, I have used a list type object which contains some dummy data. The ‘LoadData()’ function adds these dummy data to the list.

Download the source codes and check the download link:

DOWNLOAD

Conclusion

You are now ready to use the .get() method to make any type of AJAX feature in your website. Also check other similar topics in jQuery AJAX:

• 1. jQuery AJAX Events
• 2. jQuery AJAX
• 3. jQuery Load
• 4. jQuery Post

• Связанные категории:
• Ajax
  » Shorthand Methods

Returns: jqXHR

Загружает данные с сервера, используя HTTP GET запрос.

• version added: 1.0jQuery.get( url [, data] [, success(data, textStatus, jqXHR)] [, dataType] )

  url
  Тип: строка
  Адрес, на который отправляется запрос.

  data
  Тип: объект или строка
  Данные, отправляемые на сервер в виде объекта (ключ:значение) или строки.

  success(data, textStatus, jqXHR)
  Тип: функция
  Функция, вызываемая при успешном завершении Ajax запроса.

  dataType
  Тип: строка
  Тип данных, ожидаемых в качестве ответа от сервера. По умолчанию jQuery определит сам.

$.get() эквивалетна:

$.ajax({
  url: url,
  data: data,
  success: success,
  dataType: dataType
});

Функция обратного вызова success, принимает ответ от сервера, который может быть в виде XML, строки, JavaScript файла или объекта JSON, в зависимости от MIME типа ответа. Это значение так же помещается в статус ответа.

Начиная с версии 1.5, функция обратного вызова success принимает объект jqXHR (в ранних версиях объект XMLHttpRequest). В случае использования JSONP, значение второго и третьего параметры функции будет неопределённым (undefined), т.к. при кросс-доменных GET запросах, объект XHR не используется.

$.get('ajax/test.html', function(data) {
  $('.result').html(data);
  alert('Загрузка завершена.');
});

Данный код делает запрос к HTML файлу и выводит его содержимое.

Объект jqXHR

Начиная с версии 1.5, $.get() возвращает объект jqXHR, реализующий интерфейс deferred, что позволяет задавать дополнительные обработчики. Помимо стандартных для объекта deferred методов .done(), .fail() и .then(), с помощью которых можно устанавливать обработчики, в jqXHR реализованы их копии: .success(), .error() и .complete(). Это сделано для соответствия привычным названиям методов, с помощью которых устанавливаются обработчики выполнения ajax-запросов.

// запускаем ajax-запрос, устанавливаем обработчики событий.
// Возвращаемые методом $.get объект сохраним в переменной jqxhr для дальнейшего использования
var jqxhr = $.get("example.php", function() {
  alert("success");
})
.done(function() { alert("second success"); })
.fail(function() { alert("error"); })
.always(function() { alert("finished"); });
 
// установим еще один обработчик завершения запроса
jqxhr.always(function(){ alert("second finished"); });

Заметка об устаревших методах

Функции обратного действия, введённые в jQuery 1.5 устарени в версии 1.8. Вместо jqXHR.success(), jqXHR.error() и jqXHR.complete() теперь следует использовать jqXHR.done(), jqXHR.fail() и jqXHR.always().

Примеры

Сделать запрос к test.php, игнорируя ответ:

$.get("test.php");

Сделать запрос к test.php, передать данные, игнорировать ответ:

$.get("test.php", { name: "John", time: "2pm" } );

Передать массив данных на сервер, игнорируя ответ:

$.get("test.php", { 'choices[]': ["Jon", "Susan"]} );

Обработать ответ от сервера (HTML или XML в зависимости от того, что пришло):

$.get("test.php", function(data) {
  alert("Data Loaded: " + data);
});

Сделать запрос к test.cgi, предать данные, обработать ответ (HTML или XML в зависимости от того, что пришло):

$.get("test.cgi", { name: "John", time: "2pm" })
.done(function(data) {
  alert("Data Loaded: " + data);
});

Получить от сервера ответ в JSON формате и вывести его на страницу (<?php echo json_encode(array(«name»=>»John»,»time»=>»2pm»)); ?>):

$.get("test.php",
   function(data) {
     $('body').append( "Name: " + data.name ) // John
              .append( "Time: " + data.time ); //  2pm
   }, "json");

Связанные уроки:

• 

  Желтые стикеры с помощью AJAX, PHP и jQuery

  Сегодня мы создаем систему управления желтыми стикерами.

• 

  Что нового в jQuery 1.5?

  Совсем недавно, как и было обещано, группа разработчиков библиотеки jQuery выпустила новую версию своего продукта. Я попытаюсь вам рассказать о фитчах, которые вошли в свежий релиз.