Php,session Verification code inconsistent slow half shot

This kind of problem encountered once, and then forgot how to solve, so take notes

The output of $_session[' code ' is slower than the picture ' one frame ', which is also purely normal because the output picture is a connection call, and Echo $_session[' code ' is another connection call,

The latter before the former, so the output of code is always the last picture display of the value, in fact, and when we submit the data we are compared to the verification code, which is the code value is the current picture value, so do not care

Php,session Verification code inconsistent slow half shot