


PHP Answers to Frequently Asked Questions
Reposted from Joy Village
In PHP 4.2 and later versions, register_global defaults to off
If you want to get the variables submitted from another page:
Method 1: Find register_global in PHP.ini and change it Set to on.
Method 2: Put this extract($_POST);extract($_GET);(note that there must be Session_Start() before extract($_SESSION)) at the front of the receiving web page.
Method 3: One by one Read variables $a=$_GET["a"];$b=$_POST["b"], etc. Although this method is troublesome, it is safer.
PHP code:
Ob_Start();
Session_Start();
Echo "
"; <br>Echo "The _GET variables obtained on this page are:"; <br>Print_R($_GET); <br>Echo "The _POST variables obtained on this page are:"; <br> Print_R($_POST); <br>Echo "The _COOKIE variables obtained on this page are:"; <br>Print_R($_COOKIE); <br>Echo "The _SESSION variables obtained on this page are:"; <br>Print_R($_SESSION); <br>Echo "";
?>
Why when I send variables to another web page, I only get the first half, and all the ones starting with spaces are lost
PHP code:----------- -------------------------------------------------- -------------------
$Var="hello php";//Change to $Var=" hello php"; Try to get the result
$post= "receive.php?Name=".$Var;
header("location:$post");
?>
------------------ -------------------------------------------------- --------------------------
receive.php content:
PHP code:-------------------------- -------------------------------------------------- ---
Echo "
"; <br>Echo $_GET["Name"]; <br>Echo "";
?>
-------- -------------------------------------------------- ---------------------
The correct method is:
PHP code:------------------ -------------------------------------------------- ------------
$Var="hello php";
$post= "receive.php?Name=".urlencode($Var);
header("location :$post");
?>
--------------------------------------------- ----------------------------------------
You don't need to use Urldecode on the receiving page (), variables will be automatically encoded.
Standardize your SQL statements
Add "`" in front of tables and fields, so that errors will not occur due to misuse of keywords.
Of course, I do not recommend you to use keywords.
For example
$Sql="INSERT INTO `xltxlm` (`author`, `title`, `id`, `content`, `date`) VALUES ('xltxlm', 'use`', 1, 'criterion your sql string ', '2003-07-11 00:00:00')"
How do I know what functions the system supports by default?
PHP code:
------------------ -------------------------------------------------- -----------
$arr = get_defined_functions();
Function php() {
}
echo "
"; <br>Echo "Here shows the functions supported by the system All functions, and custom functions phpn"; <br>print_r($arr); <br>echo "";
?>
How to compare the number of days between two dates
PHP code:
---- -------------------------------------------------- --------------------------
$Date_1="2003-7-15";//It can also be:$ Date_1="2003-6-25 23:29:14";
$Date_2="1982-10-1";
$Date_List_1=explode("-",$Date_1);
$Date_List_2=explode("-" ,$Date_2);
$d1=mktime(0,0,0,$Date_List_1[1],$Date_List_1[2],$Date_List_1[0]);
$d2=mktime(0,0,0,$Date_List_2 [1],$Date_List_2[2],$Date_List_2[0]);
$Days=round(($d1-$d2)/3600/24);
Echo "I have already struggled $Days days^_^" ;
?>
What should you pay attention to when putting data into the database and taking it out to display on the page?
When entering the database
$str=addslashes($str);
$sql="insert into `tab` (`content`) values( '$str')";
When leaving the library
$str=stripslashes($str);
When displaying
$str=htmlspecialchars(nl2br($str));
The above introduces the answers to common frustrating questions about photoshop cs5 official Chinese version download in PHP, including the content of photoshop cs5 official Chinese version download. I hope it will be helpful to friends who are interested in PHP tutorials.

Absolute session timeout starts at the time of session creation, while an idle session timeout starts at the time of user's no operation. Absolute session timeout is suitable for scenarios where strict control of the session life cycle is required, such as financial applications; idle session timeout is suitable for applications that want users to keep their session active for a long time, such as social media.

The server session failure can be solved through the following steps: 1. Check the server configuration to ensure that the session is set correctly. 2. Verify client cookies, confirm that the browser supports it and send it correctly. 3. Check session storage services, such as Redis, to ensure that they are running normally. 4. Review the application code to ensure the correct session logic. Through these steps, conversation problems can be effectively diagnosed and repaired and user experience can be improved.

session_start()iscrucialinPHPformanagingusersessions.1)Itinitiatesanewsessionifnoneexists,2)resumesanexistingsession,and3)setsasessioncookieforcontinuityacrossrequests,enablingapplicationslikeuserauthenticationandpersonalizedcontent.

Setting the httponly flag is crucial for session cookies because it can effectively prevent XSS attacks and protect user session information. Specifically, 1) the httponly flag prevents JavaScript from accessing cookies, 2) the flag can be set through setcookies and make_response in PHP and Flask, 3) Although it cannot be prevented from all attacks, it should be part of the overall security policy.

PHPsessionssolvetheproblemofmaintainingstateacrossmultipleHTTPrequestsbystoringdataontheserverandassociatingitwithauniquesessionID.1)Theystoredataserver-side,typicallyinfilesordatabases,anduseasessionIDstoredinacookietoretrievedata.2)Sessionsenhances

PHPsessionscanstorestrings,numbers,arrays,andobjects.1.Strings:textdatalikeusernames.2.Numbers:integersorfloatsforcounters.3.Arrays:listslikeshoppingcarts.4.Objects:complexstructuresthatareserialized.

TostartaPHPsession,usesession_start()atthescript'sbeginning.1)Placeitbeforeanyoutputtosetthesessioncookie.2)Usesessionsforuserdatalikeloginstatusorshoppingcarts.3)RegeneratesessionIDstopreventfixationattacks.4)Considerusingadatabaseforsessionstoragei

Session regeneration refers to generating a new session ID and invalidating the old ID when the user performs sensitive operations in case of session fixed attacks. The implementation steps include: 1. Detect sensitive operations, 2. Generate new session ID, 3. Destroy old session ID, 4. Update user-side session information.


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