PHP prevents malicious code from refreshing a page

Session_Start (); $k =$_get[' K ']; $t =$_get[' t ']; $allowTime = 1800;//anti-refresh Time $ip = Get_client_ip (); $allowT = MD5 ($ip. $k. $t); if (!isset ($_session[$allowT])) { $refresh = true; $_session[$allowT] = time (); }elseif (Time ()-$_session[$allowT]> $allowTime) { $refresh = true; $_session[$allowT] = time (); }else{ $refresh = false; } ?> Copy Code IE6 submitted two times I have also encountered, is generally used in the picture instead of submit, the picture has a submit (), this will be submitted two times, if only submit button I did not encounter the submission two times the situation. Now tidy up: The method is basically said to be almost the page that is received is 2.php divided into two parts, part of the processing of the variables submitted, part of the page processing variable is finished with the header ("Location:". $_server[' Php_self ') Jump to Self page This section to make a judgment, if there is no post variables to skip. Of course, you can also jump to other pages. Jumping to another page will have a problem when you return, it is recommended to do in a PHP file. If the previous page passes through the variable does not meet the requirements can be forced to return Copy Code A general idea. The 2.php process if (Isset ($_post)) {Receive variable If (variable does not meet the requirements) Else Manipulating data ... if (operation completed) Header ("Location:". $_server[' php_self '); } Copy Code

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