PHP cross-origin retrieval of the previous page URL

For example, when you click the current page from www.baidu.com to jump to www.163.com, the variable $ _ SERVER [& #039; HTTP_REFERER & #039;] becomes the current page once the cross-origin is enabled, how can I break the URL of the previous page? For example, when you click the current page from www.baidu.com to jump to www.163.com, the variable $ _ SERVER ['HTTP _ referer'] becomes the current page once it is cross-origin. I want to get the previous page URL, how can this problem be solved?

Reply content:

For example, when you click the current page from www.baidu.com to jump to www.163.com, the variable $ _ SERVER ['HTTP _ referer'] becomes the current page once it is cross-origin. I want to get the previous page URL, how can this problem be solved?

$ _ SERVER ['HTTP _ referer'] will become invalid if you jump from the SSL authentication website link to your current page,
However, it is no problem to jump to $ _ SERVER ['HTTP _ referer'] To get the previous page URL between different SSL domain names.

$ _ SERVER ['HTTP _ referer'] several possible causes of missing values

• Directly tap the URL in the browser
• Hyperlink icon on windows Desktop
• Bookmarks in the browser
• Links in Word, Excel, and other content
• Links in mail management software such as outlook
• SSL Authentication Website jump
• When automatic redirect is set on the meta page, the referer url cannot be obtained in example.com.

Please add.

On the page www.163.com print_r ($ _ SERVER), check if you want

$ _ SERVER ['HTTP _ referer'] # link to the URL of the previous page of the current page