When accessing http: // localhost in the php-PHP environment, 403 Forbidden appears.

I have built a php runtime environment. in the htdocsdirectory of apache, there are two files: index.html and test. php. When I input the localhost in the browser, the browser opens the index.html file. After changing the index.html file name to index11.html, enter localhost in the browser and press Enter. on the screen, 403 ForbiddenYoudon & #39; thavepermissiontoaccessonthisserver appears. it is expected to display ind php

I have built a php runtime environment. in the htdocsdirectory of apache, there are two files: index.html and test. php. When I enter http: // localhostin the browser, the browser opens the index.html file. After changing the index.html file name to index11.html, enter http: // localhost in the browser and press Enter. the screen displays 403 Forbidden You don't have permission to access/on this server.
The hyperlinks index11.html and test. php. click it to open the corresponding page. Why does this happen? Please enlighten me. Thank you!