📄 function.session-start.html
字号:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"><html> <head> <title>Initialize session data</title> <meta http-equiv="content-type" content="text/html; charset=UTF-8"> </head> <body><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.session-set-save-handler.html">session_set_save_handler</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.session-unregister.html">session_unregister</a></div> <div class="up"><a href="ref.session.html">Session Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div><hr /><div id="function.session-start" class="refentry"> <div class="refnamediv"> <h1 class="refname">session_start</h1> <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">session_start</span> — <span class="dc-title">Initialize session data</span></p> </div> <div class="refsect1 description"> <h3 class="title">Description</h3> <div class="methodsynopsis dc-description"> <span class="type">bool</span> <span class="methodname"><b><b>session_start</b></b></span> ( <span class="methodparam">void</span> )</div> <p class="para rdfs-comment"> <b>session_start()</b> creates a session or resumes the current one based on the current session id that's being passed via a request, such as GET, POST, or a cookie. </p> <p class="para"> If you want to use a named session, you must call <a href="function.session-name.html" class="function">session_name()</a> before calling <b>session_start()</b>. </p> <p class="para"> <b>session_start()</b> will register internal output handler for URL rewriting when <i>trans-sid</i> is enabled. If a user uses <i>ob_gzhandler</i> or like with <a href="function.ob-start.html" class="function">ob_start()</a>, the order of output handler is important for proper output. For example, user must register <i>ob_gzhandler</i> before session start. </p> </div> <div class="refsect1 returnvalues"> <h3 class="title">Return Values</h3> <p class="para"> This function always returns <b><tt>TRUE</tt></b>. </p> </div> <div class="refsect1 changelog"> <h3 class="title">ChangeLog</h3> <p class="para"> <table class="informaltable"> <colgroup> <thead valign="middle"> <tr valign="middle"> <th colspan="1">Version</th> <th colspan="1">Description</th> </tr> </thead> <tbody valign="middle" class="tbody"> <tr valign="middle"> <td colspan="1" rowspan="1" align="left">4.3.3</td> <td colspan="1" rowspan="1" align="left"> As of now, calling <b>session_start()</b> while the session has already been started will result in an error of level <b><tt>E_NOTICE</tt></b>. Also, the second session start will simply be ignored. </td> </tr> </tbody> </colgroup> </table> </p> </div> <div class="refsect1 examples"> <h3 class="title">Examples</h3> <p class="para"> <div class="example"> <p><b>Example #1 A session example: <var class="filename">page1.php</var></b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// page1.php<br /><br /></span><span style="color: #0000BB">session_start</span><span style="color: #007700">();<br /><br />echo </span><span style="color: #DD0000">'Welcome to page #1'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'favcolor'</span><span style="color: #007700">] = </span><span style="color: #DD0000">'green'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'animal'</span><span style="color: #007700">] = </span><span style="color: #DD0000">'cat'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'time'</span><span style="color: #007700">] = </span><span style="color: #0000BB">time</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">// Works if session cookie was accepted<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">'<br /><a href="page2.php">page 2</a>'</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">// Or maybe pass along the session id, if needed<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">'<br /><a href="page2.php?' </span><span style="color: #007700">. </span><span style="color: #0000BB">SID </span><span style="color: #007700">. </span><span style="color: #DD0000">'">page 2</a>'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> <p class="para"> After viewing <var class="filename">page1.php</var>, the second page <var class="filename">page2.php</var> will magically contain the session data. Read the <a href="ref.session.html" class="link">session reference</a> for information on <a href="session.idpassing.html" class="link">propagating session ids</a> as it, for example, explains what the constant <b><tt>SID</tt></b> is all about. </p> <p class="para"> <div class="example"> <p><b>Example #2 A session example: <var class="filename">page2.php</var></b></p> <div class="example-contents"><div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">// page2.php<br /><br /></span><span style="color: #0000BB">session_start</span><span style="color: #007700">();<br /><br />echo </span><span style="color: #DD0000">'Welcome to page #2<br />'</span><span style="color: #007700">;<br /><br />echo </span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'favcolor'</span><span style="color: #007700">]; </span><span style="color: #FF8000">// green<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'animal'</span><span style="color: #007700">]; </span><span style="color: #FF8000">// cat<br /></span><span style="color: #007700">echo </span><span style="color: #0000BB">date</span><span style="color: #007700">(</span><span style="color: #DD0000">'Y m d H:i:s'</span><span style="color: #007700">, </span><span style="color: #0000BB">$_SESSION</span><span style="color: #007700">[</span><span style="color: #DD0000">'time'</span><span style="color: #007700">]);<br /><br /></span><span style="color: #FF8000">// You may want to use SID here, like we did in page1.php<br /></span><span style="color: #007700">echo </span><span style="color: #DD0000">'<br /><a href="page1.php">page 1</a>'</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">?></span></span></code></div> </div> </div> </p> </div> <div class="refsect1 notes"> <h3 class="title">Notes</h3> <blockquote><p><b class="note">Note</b>: If you are using cookie-based sessions, you must call <b>session_start()</b> before anything is outputted to the browser. <br /> </p></blockquote> <blockquote><p><b class="note">Note</b>: Use of <a href="zlib.configuration.html#ini.zlib.output-compression" class="link">zlib.output_compression</a> is recommended rather than <a href="function.ob-gzhandler.html" class="function">ob_gzhandler()</a> <br /> </p></blockquote> </div> <div class="refsect1 seealso"> <h3 class="title">See Also</h3> <p class="para"> <ul class="simplelist"> <li class="member"><var class="varname"><a href="reserved.variables.session.html" class="classname">$_SESSION</a></var></li> <li class="member"> The <a href="session.configuration.html#ini.session.auto-start" class="link">session.auto_start</a> configuration directive </li> <li class="member"><a href="function.session-id.html" class="function" rel="rdfs-seeAlso">session_id()</a></li> </ul> </p> </div> </div><hr /><div style="text-align: center;"> <div class="prev" style="text-align: left; float: left;"><a href="function.session-set-save-handler.html">session_set_save_handler</a></div> <div class="next" style="text-align: right; float: right;"><a href="function.session-unregister.html">session_unregister</a></div> <div class="up"><a href="ref.session.html">Session Functions</a></div> <div class="home"><a href="index.html">PHP Manual</a></div></div></body></html>⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -