Index. php is blank during access

Index. php is blank when accessing index. php. it is blank when accessing index. php, and nothing is displayed. it can still be accessed normally last month, giving users full control of permissions is useless ., View the HTTP status code. 500,403,404 or 502. at this time, it is King to output the php error message. discard IE browser and get started with chrome. in the Network tab of the developer tool, check whether the index. php of the request is blank during access.
Index. php is blank during access, and nothing is displayed. it can still be accessed normally last month, giving users full control of permissions.

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View the HTTP status code. 500,403,404 or 502.

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At this time, the php error message is output.
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Discard IE browser and get started with chrome. on the Network tab of the developer tool, check the returned status code of the request.
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200, but nothing is output, there is a possibility that:
Your program file has no output action.
Or some logic errors may occur. The PHP program exits automatically.
We recommend that you modify the program file and add echo "++ \ n". microtime (true) before and after the code to check whether the program file has changed.
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If a fatal error occurs in the program, go back and close the error report online.
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Is index. php linked to a database?
If yes, do not connect to the database first. just try echo something. If no output is available, it should be a coding problem.
If it can be output, it is estimated that there is a problem with the database, core file or configuration file.
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What is written on your index. php page? is it a front-end controller.