Ii. Use of jsonp to reference to common limitations

Co-source policy 1. What is co-source

If the two pages have the same protocols, domain names and ports, then the two pages belong to the same source, which is different if one is different

2. Purpose of the co-source policy

The co-source policy is designed to ensure the security of user information and prevent the theft of data from malicious websites. The original co-source policy is the c set by a website on the client sideLookie, website b is not accessible

With the development of the internet, the homogenous policy has become increasingly stringent, with one of the provisions being the inability to send ajax requests to non-consistent addresses, and if requested, the browser will miss。

Ii. Use of jsonp to address congener limits 1. What is jsonp

Jsonp is the abbreviation of json with padding, which does not belong to the ajax request, but it can simulate ajax request, which is an unofficial cross-domain solution and only supports the get request

How does jsopn work

Some web pages have specific cross-domain capabilities, e. G. Amg, lInk, ifI'm sorryCript

Jsopn is using sCript's cross-domain capability to send requests

3. Use of jsonp

(1) request address of server from different sources in sIn the src attribute of the cript tag

"www. Example. Com"I'm sorry

(2) server-end response data must be a function call, and data that is really sent to the client needs to be used as a function call parameter

(3) define function under client global domainf

Funaction {\data}

Set function definition in sCript tag front and defined in global domain

(4) processing of data returned by the server within fn

Iii. Jsopn code optimizing 1Cript sent requests into dynamic requests

    Click to send request
    I'm sorry. Function n(data){
okay, console'the client function is calledI'm sorry. Console. Log (json. Stream(data));
♪ i'm sorry ♪I'm sorryI'm sorry. Co=dI'm sorry, i'm sorry'buttonI'm sorry. I don't knowNclick = effect(){
coI don't knowCript =dI'm sorry, i'm sorry'sCriptI'm sorry. SI'm sorry, cript'http://localhost:30000/server2';
dI don't know, document. Body. Appendchild(e) cript;
///resumption of sending
sI don't knowNload = effect(){
dI don't know what you're talking about(e) cript;
♪ i'm sorry ♪
♪ i'm sorry ♪I'm sorry

Client needs to pass the function name to the server end

Before the client changes the name of the function to influence the server to change repeatedly

    Click to send request
    I'm sorry. Function n(data){
okay, console'the client function is calledI'm sorry. Console. Log (json. Stream(data));
♪ i'm sorry ♪I'm sorry== sync, corrected by elderman == @elder manI'm sorry

I don't know'/server2 1', (req, res) = {
i don't know'access-control-allow-origin'..,'*I'm sorry. Co{\chffffff}{\ch00ff00} {\chffffff}{\ch00ff00} {\chffffff}{\ch00ffff}
coNst result =fnname+'(name: "chang woo chan")';
res. Send (result);
♪ i'm not sure ♪

3. Encapsulating jsonp functions to facilitate the sending of requests

I don't know

Section jsonp(options){
/ dynamic creationsCript tag
coI don't knowCript =dI'm sorry, i'm sorry'sCriptI'm sorry.
/ yeah, yeah, yeah, yeahCript adds src property
s= options. Url;
/ willsCript add to page
dI don't know, document. Body. Appendchild(e) cript;
// deleting after jsonp loadsCript tag
sI don't knowNload=()=>
dI don't know what you're talking about(e) cript;
♪ i'm sorry ♪
♪ i'm sorry ♪

    Click to send request
    ".././jsonp. Js"I'm sorryI'm sorry. Function n(data){
okay, console'the client function is calledI'm sorry. Console. Log (json. Stream(data));
♪ i'm sorry ♪I'm sorryI'm sorry. Co=dI'm sorry, i'm sorry'buttonI'm sorry. I don't knowNclick = effect(){
jsonp({)
url:'http://localhost: 3,000/server2 1? Callback=fn♪ i'm sorry ♪
♪ i'm not sure ♪
♪ i'm sorry ♪I'm sorry

4. Functions associated with sealed jsonp functions, functions

The call function in jsonp is no longer a global function

Generate a random function name to prevent multiple calls to the jsonp function, overwrite the front side of the back

Section jsonp(options){
/ dynamic creationsCript tag
coI don't knowCript =dI'm sorry, i'm sorry'sCriptI'm sorry.
/ /jsonp calling function when successful/failed is no longer a global function
/ random function name to prevent multiple calls to the jsonp function, override the front side of the back
coNst nnname='myjsonp' + math. Random(). Tostrring(). Replace()'cause...'..,♪ i'm sorry ♪I'm sorry. Windows [fnname] = options. Access;
/ yeah, yeah, yeah, yeahCript adds src property
s= options. Url +'? Callback'+fnname;
/ willsCript add to page
dI don't know, document. Body. Appendchild(e) cript;
// deleting after jsonp loadsCript tag
sI don't knowNload=()=>
dI don't know what you're talking about(e) cript;
♪ i'm sorry ♪
♪ i'm sorry ♪

5. Collapse the requested parameters behind the requested address

/close request parameters to the back of the address
var params =♪ i'm sorry ♪';
for (var attr in options. Data)
params +='""'+attr '+'=' + options. Data [attr];
♪ i'm sorry ♪
s= options. Url +'? Callback'+fnname+params;