Example of getJSON() usage in jQuery ajax_jquery

Example
Load JSON data from test.js and display a name field data in the JSON data:

Copy code The code is as follows:

$.getJSON("test.js", function(json){
alert("JSON Data: " json.users[3].name);
});

Definition and usage
Load JSON data via HTTP GET request.

In jQuery 1.2, you can load JSON data from other domains by using a JSONP-style callback function, such as "myurl?callback=?". jQuery will automatically replace ? with the correct function name to execute the callback function. Note: The code after this line will be executed before this callback function is executed.

Grammar
jQuery.getJSON(url,[data],[callback])

Parameter Description
url The URL address of the page to be loaded.
data Key / value parameters to be sent.
callback The callback function executed when loading is successful.

Detailed description

This function is the abbreviation of Ajax function, which is equivalent to:

Copy code The code is as follows:

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

Data sent to the server can be appended to the URL as a query string. If the value of the data parameter is an object (map), it is converted to a string and URL-encoded before being appended to the URL.

The return data passed to callback can be a JavaScript object or an array defined in a JSON structure, and is parsed using the $.parseJSON() method.

More examples

Example 1
Load the 4 latest cat pictures from the Flickr JSONP API:

HTML code:

Copy code The code is as follows:

jQuery code:

Copy code The code is as follows:

$.getJSON("http://api.flickr.com/services/feeds/photos_public.gne?
tags=cat&tagmode=any&format=json&jsoncallback=?", function(data){
$.each(data.items, function(i,item){
$("").attr("src", item.media.m).appendTo("#images");
If ( i == 3 ) return false;
});
});

Example 2
Load JSON data from test.js, append parameters, and display a name field data in the JSON data:

Copy code The code is as follows:

$.getJSON("test.js", { name: "John", time: "2pm" }, function(json){
alert("JSON Data: " json.users[3].name);
});