1. http common status codes
Beginning 2 ( request successful ) expressed successfully processed the request status code.
3 at the beginning ( the request is redirected ) to fulfill the request indicates the need for further operations. Typically, these status codes for redirection.
4 beginning ( Request error ) These status codes indicate that the request may be wrong, preventing the processing server.
Beginning 5 ( Server Error ) These status codes indicate internal server error occurred while trying to process the request. These errors may be wrong server itself, not with the request.
2. CSS let elemental level center of what? Please write the corresponding style code.
If the element is within ⾏ element disposed ⽗ elements text-align: center if the element width is fixed, may be provided around margin to auto;
if the element is absolute positioning, provided ⽗ element position is relative, an element disposed left: 0; right: 0; margin: auto;
Using flex-box layout, justify-content attribute specified center; display set tabel-ceil.
Angle 3.7 - fifteen is how much?
(1) seven, seven hour; 15 minutes, the minute hand 3, a difference of the intermediate 4 digits. Between the two numbers is 30 degrees, it is 120 degrees, as if nothing wrong.
(2) quarter past seven: seven attention when the hour hand is indeed at number 7, but quarter past seven when gone. Minute hand go 1/4 turn, 1/4 hour intervals is gone (30 * 1/4 = 7.5 °). It is 120 + 7.5 = 127.5 °.
