jquery cross-domain request example sharing (jquery sends ajax request)_jquery

getJSON is commonly used in jQuery to call and obtain the remote JSON string, convert it into a JSON object, and if successful, execute the callback function. The prototype is as follows:

jQuery.getJSON( url, [data], [callback] ) loads JSON data across domains.

url: the address to send the request data: (optional) key/value parameters to be sent callback: (optional) callback function when loading is successful is mainly used for the client to obtain the server JSON data. Simple example:

Server script, return JSON data:

Copy code The code is as follows: // $.getJSON.php $arr =array("name"=>"zhangsan", "age"=>20); $jarr=json_encode($arr); echo $jarr; Note two points: First: Before returning to the client, use the PHP function json_encode to encode the returned data. Second: echo is used to return to the client, not return.

The following is the core client code:

Copy code The code is as follows: function getjs() { $.getJSON("$.getJSON.php", {}, function(response){ alert(response.age); }); }

Since the return value is encoded in JSON in PHP, you must use getJSON to call the PHP file to obtain the data. At the same time, you can notice that the data obtained through getJSON has become an object array, and you can use response.name and response.age to get the return value intuitively.

jquery provides the $.getJSON method, allowing us to implement cross-domain ajax requests, but the content on jqueryAPI is too little. How to use $.getJSON, and what kind of database should be returned by the requesting website so that $.getJSON can obtain it? , I will use a practical example to illustrate below.

The back-end uses PHP. One of the main functions of the following code is to provide an interface for appointment registration. The data that needs to be passed in are: user name, contact number and address:

Copy code The code is as follows: /*Appointment registration execution interface*/ case "yuyue_interface": $name = trim($_GET['name']); $phone = trim($_GET['phone']); $addr = trim($_GET[' addr']); $dt = date("Y-m-d H:i:s"); $cb = $_GET['callback']; if($name == "" || $name == NULL){ echo $cb."({code:".json_encode(1)."})"; }elseif($phone == "" || $phone == NULL ){ echo $cb."({code:".json_encode(2)."})"; }elseif($addr == "" || $addr == NULL){ echo $cb."({code:".json_encode(3)."})"; }else{ $db->execute("insert into tb_yuyue (realname,telphone,danwei,dt, ischeck) values ('$name','$phone','$addr','$dt',0)"); echo $cb."({code:".json_encode(0)."} )"; } exit; break; Then comes the front-end processing:

Copy code The code is as follows: $(document).ready(function(){ //The following 3 parameters are required for reservation registration var name = "name"; //varchar type, with a maximum length of 8 digits (4 Chinese characters) var phone = "phone"; // Varchar type, length is 11 bits var addr = "addr"; //varchar type, length is up to 500 bits (250 Chinese characters) $.getJSON("http://request website address/data. php?ac=yuyue_interface&name=" name "&phone=" phone "&addr=" addr "&callback=?", function(data){ if(data.code==1){ //Customized code alert("Name cannot be empty"); }else if(data.code==2){ //Custom code alert("Mobile phone cannot be empty"); }else if(data.code==3){ //Customized code alert("The unit cannot be empty"); }else{ //Customized code alert("appointment successful"); } }); }); It should be noted that in the back-end php code, the " &callback=? " passed in must also be output, such as:

Copy code The code is as follows: $cb = $_GET['callback']; echo $cb."({code:".json_encode(4)."})"; The above is a simple $.getJSON test. Through this test, we can learn How to use $.getJSON, you can also learn how to make an interface for others to make cross-domain requests.