Parameter attributes and functions of the ajax method in jquery: 1. options attribute, used to set ajax requests; 2. async, the default is an asynchronous request, and when set to false, it is a synchronous request; 3. cache, used Used to set the cache interface; 4. data, used to set the data sent to the server; 5. global, used to set whether to trigger local ajax events; 6. password, used to respond to the password for HTTP access authentication requests, etc.
The operating environment of this tutorial: windows10 system, jquery3.6.0 version, Dell G3 computer.
The ajax() method loads remote data through HTTP requests.
This method is the underlying AJAX implementation of jQuery. For simple and easy-to-use high-level implementations, see $.get, $.post, etc. $.ajax() returns the XMLHttpRequest object it created. In most cases you won't need to manipulate this function directly unless you need to manipulate less commonly used options for more flexibility.
In the simplest case, $.ajax() can be used directly without any parameters.
Note: All options can be set globally through the $.ajaxSetup() function.
Syntax
jQuery.ajax([settings])
settings
Optional. A collection of key-value pairs used to configure Ajax requests.
You can set the default value of any option through $.ajaxSetup()
options
Type: Object
Optional. AJAX request settings. All options are optional.
async
Type: Boolean
Default value: true. By default, all requests are asynchronous. If you need to send synchronous requests, set this option to false.
Note that synchronous requests will lock the browser, and other user operations must wait for the request to be completed before they can be executed.
beforeSend(XHR)
Type: Function
A function that can modify the XMLHttpRequest object before sending the request, such as adding a custom HTTP header.
The XMLHttpRequest object is the only parameter.
This is an Ajax event. If false is returned, this ajax request can be canceled.
cache
Type: Boolean
Default value: true, the default is false when dataType is script and jsonp. Set to false to not cache this page.
New features in jQuery 1.2.
complete(XHR, TS)
Type: Function
Callback function after the request is completed (called after the request is successful or failed).
Parameters: XMLHttpRequest object and a string describing the request type.
This is an Ajax event.
contentType
Type: String
Default value: "application/x-www-form-urlencoded". Content encoding type when sending information to the server.
The default value is suitable for most situations. If you explicitly pass a content-type to $.ajax() then it will definitely be sent to the server (even if there is no data to send).
context
Type: Object
This object is used to set the context of Ajax-related callback functions. In other words, let this in the callback function point to this object (if this parameter is not set, then this will point to the options parameter passed when calling this AJAX request). For example, specifying a DOM element as the context parameter will set the context of the success callback function to this DOM element.
Like this:
$.ajax({ url: "test.html", context: document.body, success: function(){ $(this).addClass("done"); }});
data
Type: String
The data sent to the server. Will be automatically converted to request string format. Appended to the URL in GET requests. See the processData option description to disable this automatic conversion. Must be in Key/Value format. 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'.
dataFilter
Type: Function
Function for preprocessing 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.
dataType
Type: String
The expected data type returned by the server. If not specified, jQuery will automatically make intelligent judgments based on the MIME information of the HTTP package. For example, the XML MIME type is recognized as XML. In 1.4, JSON will generate a JavaScript object, and script will execute the script. The data returned by the server will then be parsed based on this value and passed to the callback function. Available values:
"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 cached automatically. Unless the "cache" parameter is set. Note: When making remote requests (not under the same domain), all POST requests will be converted into GET requests. (Because the DOM script tag will be used to load)
"json": Returns JSON data.
"jsonp": JSONP format. When calling a function using JSONP form, such as "myurl?callback=?" jQuery will automatically replace ? with the correct function name to execute the callback function.
"text": Returns a plain text string
error
Type: Function
Default value: Automatic judgment (xml or html). This function is called when the request fails.
has the following three parameters: XMLHttpRequest object, error message, (optional) captured exception object.
If an error occurs, the error message (the second parameter) may be "timeout", "error", "notmodified" and "parsererror" in addition to null.
This is an Ajax event.
global
Type: Boolean
Whether to trigger the global AJAX event. Default value: true. Setting to false will not trigger global AJAX events such as ajaxStart or ajaxStop which can be used to control different Ajax events.
ifModified
Type: Boolean
Get new data only when the server data changes. Default value: false. Use HTTP packet Last-Modified header information to determine. As of jQuery 1.4, it also checks the server-specified 'etag' to make sure the data has not been modified.
jsonp
Type: String
Override 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 {jsonp:'onJsonPLoad'} which will cause "onJsonPLoad=?" to be passed to the server.
jsonpCallback
Type: String
Specify a callback function name for the jsonp request. This value will be used instead of the random function name automatically generated by jQuery. This is mainly used to allow jQuery to generate unique function names so that it is easier to manage requests and provide callback functions and error handling. You can also specify this callback function name when you want the browser to cache GET requests.
password
Type: String
Password used to respond to HTTP access authentication requests
processData
Type: Boolean
Default value: true. By default, the data passed in through the data option, if it is an object (technically speaking, as long as it is not a string), will be processed and converted into a query string to match the default content type "application/x-www-form-urlencoded" ". Set to false if you want to send DOM tree information or other information that you don't want to convert.
scriptCharset
Type: String
Only when the dataType is "jsonp" or "script" when requesting, and the type is "GET" Used to force modification of charset. Usually only used when the local and remote content encodings are different.
success
Type: Function
The callback function after the request is completed.
The parameter is the data returned by the server and processed according to the dataType parameter; a string describing the status.
This is an Ajax event.
traditional
Type: Boolean
Set to true if you want to serialize data in the traditional way. Please refer to the jQuery.param method under the Tools category.
timeout
Type: Number
Set the request timeout (milliseconds). This setting overrides the global setting.
type
Type: String
Default value: "GET"). Request method ("POST" or "GET"), default is "GET". Note: Other HTTP request methods such as PUT and DELETE can also be used, but are only supported by some browsers.
url
Type: String
Default value: Current page address. The address to send the request to.
username
Type: String
Username used to respond to HTTP access authentication requests.
xhr
Type: Function
Needs to return an XMLHttpRequest object. The default is ActiveXObject under IE and XMLHttpRequest otherwise. Used to override or provide an enhanced XMLHttpRequest object. This parameter was not available before jQuery 1.3.
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