A .http with https
(One)
(1) HTTPS protocol requires ca apply for a certificate, a certificate and most are free.
(2) HTTP transmit information in the form of plain text, https is encrypted with ssl security transmission protocol.
(. 3) HTTP and https use is completely different connections, with the port are not the same, the former is 80 (sometimes 8080), which is 443.
(4) is connected http simple, stateless; the HTTPS protocol is based on HTTP protocol, with the SSL layer, it may be constructed encrypted transmission, network authentication protocol, the http protocol than security.
（二）http=>https
(1) modify the code, modify the external reference http js css file to https, does not support https if external links need to download a static file to the project referenced in the project.
(2) purchase SSL security certificates, and placed in the appropriate directory.
(3) modify the configuration file, SSL support, and the introduction of a security certificate configuration file.
This is a general step, the specific configuration required for the specific application environment.
二. var、let、const
Three. Ajax
(A) ajax stands for "Asynchronous Javascript And XML", is not a new technology, are grouped together by javascript, xml, XMLHttpRequest, can realize the function asynchronous submitted an application to create interactive web pages development technology.
- Var variable definition, there is no concept of a block, across the block access can not access across function.
- Variables let definition, can only be accessed in block scope, can not cross block access, it can not cross function access.
- const is used to define the constants, it must be initialized (i.e., must be assigned) when used, can only be accessed at block in scope, and can not be modified.
(B) the difference between synchronous and asynchronous submitted
Synchronization Submission: When a user sends a request, the current page may not be used, the page server responds to the client, the response is complete, the user can use page.
Asynchronous Submit: When a user sends a request, can continue to use the current page, when the asynchronous data in response to the page request, the page data is displayed.
(C) ajax features (asynchronous submission)
You can quickly create dynamic Web pages; without the need to reload the entire page, to update part of the page; improve the user experience;
https://blog.csdn.net/p358278505/article/details/78718283
