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This article mainly introduces the Python crawler Ajax dynamic loading knowledge points, has a certain reference value, interested friends can refer to, I hope you can learn a lot after reading this article, the following let the editor take you to understand it.

Python crawler Ajax dynamic loading knowledge points explain, Ajax dynamic loading from the url of the web page to load the source code of the web page, the browser will execute the JavaScript program. These programs will load more content and transfer it to the web page.

The data that the page does not want to be obtained by the crawler is loaded dynamically using Ajax, which causes great trouble for the crawler. If a crawler does not have a js engine, or has a js engine, but does not have a solution for dealing with js returns, or has a js engine, but there is no way to make the site display enabled script settings. Based on these conditions, ajax dynamic loading is quite effective against crawlers.

Ajax dynamic loading works as follows: after loading the source code of the web page from the url of the web page, the JavaScript program will be executed in the browser. These programs will load more content and transfer it to the web page. This is why some web pages have no data when they climb its URL directly.

How to handle it: if you use the review element to analyze the corresponding link of the "request" (method: right-click the → review element → Network → to clear, click "load more", appear the corresponding GET link to find the Type for text/html, click, view the get parameter or copy RequestURL), cycle the process. If there is a page before "request", analyze and deduce page 1 according to the URL of the previous step. And so on, grab the data of the Ajax address. The returned json is parsed using json in requests, and the output json data can be formatted using eval () to dictionary processing.

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