What are the ajax attributes? Detailed introduction to ajax attributes (example attached)

This article mainly talks about the attributes of ajax. It contains almost all the commonly used and uncommon attributes of ajax. If you want to learn, start reading this article quickly

I can’t always remember the ajax method parameters in jquery, so record them here.

1.url:
Requires a String type parameter, (default is the current page address) the address to which the request is sent.

2.type:
Requires parameters of String type, and the request method (post or get) defaults to get. Note that other http request methods such as put and delete can also be used, but are only supported by some browsers.

3.timeout:
Requires a parameter of type Number and sets the request timeout (milliseconds). This setting will override the global setting of the $.ajaxSetup() method.

4.async:
Requires Boolean type parameters, the default setting is true, and all requests are asynchronous requests. If you need to send synchronous requests, set this option to false. Note that a synchronous request will lock the browser, and the user must wait for the request to complete before other operations can be performed.

5.cache:
Requires parameters of Boolean type, the default is true (when the dataType is script, the default is false), setting it to false will not cause the browser to Load request information in cache.

6.data:
Requires parameters of type Object or String, data sent to the server. If it is not a string, it will be automatically converted to string format. The get request will be appended to the url. To prevent this automatic conversion, check the processData option. The object must be in key/value format, for example {foo1:"bar1",foo2:"bar2"} is converted to &foo1=bar1&foo2=bar2. If it is an array, JQuery will automatically assign the same name to different values. For example, {foo:["bar1","bar2"]} is converted to &foo=bar1&foo=bar2.

7.dataType:
Requires parameters of String type, expected data type returned by the server. If not specified, JQuery will automatically return responseXML or responseText based on the http package mime information and pass it as a callback function parameter. The available types are as follows:
xml: Returns an XML document that can be processed with JQuery.
html: Returns plain text HTML information; the included script tag will be executed when inserted into the DOM.
script: Returns plain text JavaScript code. Results are not automatically cached. Unless cache parameters are set. Note that when making remote requests (not under the same domain), all post requests will be converted into get requests.
json: Return JSON data.
jsonp: JSONP format. When calling a function using the SONP form, such as myurl?callback=?, JQuery will automatically replace the last "?" with the correct function name to execute the callback function.
text: Returns a plain text string.

8.beforeSend:
is required to be a parameter of Function type. You can modify the function of the XMLHttpRequest object before sending the request, such as adding a custom HTTP header. If false is returned in beforeSend, this ajax request can be canceled. The XMLHttpRequest object is the only parameter.
Function (xmlhttprequest) {
this; // Call the options parameter passed during the Ajax request
}
## 9.Complete : Requirement to the Function type Parameter, callback function called after the request is completed (called when the request succeeds or fails). Parameters: XMLHttpRequest object and a string describing the successful request type.
                                                                                           
                                                                                                    using using using using         through using ’ ’s ’ ’ s using using ’s ’s to assemble through a ’s ‐ to ‐‐‐‐‐ function(XMLHttpRequest, ​Type parameter, the callback function called after the request is successful, has two parameters.
        (1) Data returned by the server and processed according to the dataType parameter.
(2) Describe the string of the state.

Function (Data, TextStatus) {

// Data may be XMLDOC, JSONOBJ, HTML, Text, etc. #11.error
:
is required to be a parameter of Function type, which is the function to be called when the request fails. This function has three parameters, namely XMLHttpRequest object, error message, and captured error object (optional). The ajax event function is as follows:
function(XMLHttpRequest, textStatus, errorThrown){
Normally only one of textStatus and errorThrown contains information
this; //The options parameters passed when calling this ajax request
       }

12.contentType:
is required to be a String type parameter. When sending information to the server, the content encoding type defaults to "application/x-www-form -urlencoded". This default value is suitable for most applications.

When the data format sent is json, the encoding type set is: "
application/json; charset=utf-8"

13.dataFilter :
requires parameters of Function type, a function that preprocesses the original data returned by Ajax. Provide two parameters: data and type. data is the original data returned by Ajax, and type is the dataType parameter provided when calling jQuery.ajax. The value returned by the function will be further processed by jQuery.

          function(data, type){

                                                                                                                                                                                                                                                                               

14.dataFilter:
requires parameters of Function type, a function that preprocesses the original data returned by Ajax. Provide two parameters: data and type. data is the original data returned by Ajax, and type is the dataType parameter provided when calling jQuery.ajax. The value returned by the function will be further processed by jQuery.
FUNCTION (Data, Type) {
// Back to the processing data
Return data;
}

# 15.global : Requirement It is a parameter of Boolean type and defaults to true. Indicates whether to trigger the global ajax event. Setting to false will not trigger global ajax events, ajaxStart or ajaxStop can be used to control various ajax events.

16.ifModified: is required to be a Boolean type parameter, and the default is false. Only get new data when server data changes. The basis for determining server data changes is the Last-Modified header information. The default value is false, which means header information is ignored.

17.jsonp：Requires parameters of String type to rewrite the name of the callback function in a jsonp request. This value is used to replace the "callback" part of the URL parameter in a GET or POST request such as "callback=?". For example, {jsonp:'onJsonPLoad'} will cause "onJsonPLoad=?" to be passed to the server.

18.username: is required to be a String type parameter, used to respond to the username of the HTTP access authentication request.

19.password: is required to be a String type parameter, which is the password used to respond to the HTTP access authentication request.

20.processData: Requires a Boolean type parameter, the default is true. By default, the data sent will be converted to an object (technically not a string) to match the default content type "application/x-www-form-urlencoded". If you want to send DOM tree information or other information that you do not want to convert, set it to false.

21.scriptCharset: Requires parameters of String type. It will only be used for coercion when the dataType is "jsonp" or "script" during the request, and the type is GET. Modify the character set (charset). Usually used when the local and remote content encodings are different.
(If you want to see more, go to the PHP Chinese website AJAX Development Manual column to learn)

Case code:

$(function(){
    $('#send').click(function(){
         $.ajax({
             type: "GET",
             url: "test.json",
             data: {username:$("#username").val(), content:$("#content").val()},
             dataType: "json",
             success: function(data){
                         $('#resText').empty();   //清空resText里面的所有内容
                         var html = '';
                         $.each(data, function(commentIndex, comment){
                               html += '<p class="comment"><h6>' + comment['username']                                         + ':</h6><p class="para"&#39; + comment[&#39;content&#39;]                                         + &#39;</p></p>';
                         });
                         $('#resText').html(html);
                      }
         });
    });
});

22. By the way, the $.each() function:$.each() function is different from the each() method of the JQuery object. It is a global function that does not operate on the JQuery object, but uses an array or object. As the first parameter, take a callback function as the second parameter. The callback function has two parameters: the first is the member of the object or the index of the array, and the second is the corresponding variable or content. An example of $.each() is as follows:

var json = '[{"id":"1","tagName":"apple"},{"id":"2","tagName":"orange"},
{"id":"3","tagName":"banana"},{"id":"4","tagName":"watermelon"},
{"id":"5","tagName":"pineapple"}]';

$.each(json, function(idx, obj) {
    alert(obj.tagName);
});

each() method of Jquery object As follows:

$("button").click(function(){
  $("li").each(function(){
    alert($(this).text())
  });
});

Remarks: function(index,element)

• index - The index position of the selector

• element - The current element (you can also use " this" selector)

This article ends here (if you want to see more, go to the PHP Chinese website AJAX User Manual column to learn), there are If you have any questions, you can leave a message below.

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