How to request data across domains with jquery front-end

In front-end development, it is often necessary to request data from different servers. However, due to the restrictions of the same-origin policy, data cannot be directly requested across domains. To solve this problem, we can use the method provided by jQuery.

1. What is cross-domain request data

Cross-domain request data refers to obtaining data by sending a request to another server through the client (browser) in front-end development data. For security reasons, browsers restrict requests from servers with different origins. Same origin means that the protocol, port and host name of the two pages are the same. A common situation for requesting data across domains is to request data from another server through Ajax on the front-end page.

2. Why cross-domain data request is needed

Cross-domain data request is a very common situation in front-end development. There are several reasons:

• Separate front-end and back-end logic: Front-end and back-end development are often completed by two different teams, and they require different servers to run their respective codes. By requesting data across domains, the logical separation between the front end and the back end can be made clearer.
• Save resources: Some commercial services may only provide API interfaces and not front-end resources. At this time, if you need to call the service, you need to request data across domains.
• Multiple front-end servers share data: Sometimes, different front-end servers need to access the same back-end service, and in this case, cross-domain data requests are required.

3. Methods to solve cross-domain data request

Due to the restrictions of the same-origin policy, cross-domain data cannot be requested directly, but we can use the following solutions:

• JSONP: Although JavaScript does not natively support cross-domain requests, you can use the src attribute of the
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