This time I will bring you a detailed explanation of the implementation of JS same-origin and cross-domain access. What are the precautions for the implementation of JS homology and cross-domain access? The following is a practical case, let’s take a look.
1. What is the same-origin policy
#To understand cross-domain, you must first understand the same-origin policy. The Same Origin Policy is a very important security policy implemented on browsers for security reasons.
What is the same origin:
URL consists of protocol, domain name, port and path. If the protocol, domain name and port of two URLs are the same, it means that they have the same origin. .
Same origin policy:
The browser's same origin policy restricts "documents" or scripts from different sources from reading or setting the current "document" certain attributes. (White hat talks about web security [1])
Scripts loaded from one domain are not allowed to access document attributes of another domain.
For example:
For example, a malicious website page embeds a bank’s login page through an iframe (the two are from different sources). If there is no same-origin restriction, the javascript script on the malicious webpage will The username and password can be obtained when the user logs into the bank.
In the browser, tags such as
![[Web front-end] Node.js quick start](https://img.php.cn/upload/course/000/000/067/662b5d34ba7c0227.png)
