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    $_SESSION

    $_SESSION — Session 变量

    说明

    当前脚本可用 SESSION 变量的数组。更多关于如何使用的信息，参见 Session 函数 文档。

    注释

    注意:

    “Superglobal”也称为自动化的全局变量。这就表示其在脚本的所有作用域中都是可用的。不需要在函数或方法中用 global $variable; 来访问它。

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    用户贡献的备注 3 notes

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    104
    Tugrul
    9 years ago
    Creating New Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    ?>
    Getting Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    /*session created*/
    echo $_SESSION["newsession"];
    /*session was getting*/
    ?>
    Updating Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    /*it is my new session*/
    $_SESSION["newsession"]=$updatedvalue;
    /*session updated*/
    ?>
    Deleting Session
    ==========================
    <?php
    session_start    ();
    /*session is started if you don't write this line can't use $_Session global variable*/
    $_SESSION["newsession"]=$value;
    unset(    $_SESSION["newsession"]);
    /*session deleted. if you try using this you've got an error*/
    ?>
    up
    11
    bohwaz
    16 years ago
    Please note that if you have register_globals to On, global variables associated to $_SESSION variables are references, so this may lead to some weird situations.

    <?php

    session_start    ();

    $_SESSION['test'] = 42;
    $test = 43;
    echo     $_SESSION['test'];

    ?>

    Load the page, OK it displays 42, reload the page... it displays 43.

    The solution is to do this after each time you do a session_start() :

    <?php

    if (ini_get('register_globals'))
    {
    foreach (    $_SESSION as $key=>$value)
    {
    if (isset(    $GLOBALS[$key]))
    unset(    $GLOBALS[$key]);
    }
    }

    ?>
    up
    -1
    opajaap at opajaap dot nl
    11 years ago
    Be carefull with $_SESSION array elements when you have the same name as a normal global.

    The following example leads to unpredictable behaviour of the $wppa array elements, some are updated by normal code, some not, it is totally unpredictable what happens.

    <?php
    global $wppa;
    $wppa = array( 'elm1' => 'value1', 'elm2' => 'value2', ....etc...);

    if ( !     session_id() ) @ session_start();
    if ( ! isset(    $_SESSION['wppa']) $_SESSION['wppa'] = array();

    if ( ! isset(    $_SESSION['wppa']['album']) ) $_SESSION['wppa']['album'] = array();
    $_SESSION['wppa']['album'][1234] = 1;

    $wppa['elm1'] = 'newvalue1';

    print_r($_SESSION);
    ?>
    This will most likely display Array ( [wppa] => Array ( [album] => Array ( [1234] => 1 ) [elm1] => 'newvalue1' [elm2] => 'value2' ... etc ...
    But setting $wppa['elm1'] to another value or referring to it gives unpredictable results, maybe 'value1', or 'newvalue1'.

    The most strange behaviour is that not all elements of $wppa[xx] show up as $_SESSION['wppa'][xx].
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