about how PHP uses tokens to prevent forms from repeating submissions

This article mainly describes the PHP use token to prevent the form of repeated submission method, by generating an encrypted random number into the session token variable, while putting the value into the form of hidden submissions, to prevent the form of repeated submissions, the need for friends can refer to the next

<?php/** PHP uses tokens to prevent forms from repeating a form * This processing method is purely for beginners ' reference */session_start (); function Set_token () {  $_session[' token '] = MD5 (Microtime (TRUE));} function Valid_token () {  $return = $_request[' token '] = = = $_session[' token ']? true:false;  Set_token ();  return $return;} Generates a tokenif (!isset ($_session[' token ') "If token is empty) | | $_session[' token ']== ') {  set_token ();} if (isset ($_post[' test ')) {  if (!valid_token ()) {    echo "token error";  } else{    Echo ' successfully submitted, Value: '. $_post[' test ';  }}? ><form method= "POST" action= "" >  <input type= "hidden" name= "token" value= "<?php echo $_session[" Token ']?> ' >  <input type= "text" name= "test" value= "Default" >  <input type= "Submit" value= "submit "/></form>

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