Định nghĩa và sử dụng
Sự khác nhau giữa HTML và XHTML
Cấu trúc<abbr title=""></abbr> Show title="" là thuộc tính trong <abbr>, nhằm giải thích nghĩa cho từ viết tắt. Ví dụHtml viết:<p><abbr title="World Health Organization">WHO</abbr> là một Tổ chức Y tế Thế giới.</p> Hiển thị trình duyệt:WHO là một Tổ chức Y tế Thế giới. Trong đoạn trên, ta đã biết "WHO" là viết tắt của "World Health Organization". Trình duyệt hỗ trợTag <abbr> được hỗ trợ trong đa số các trình duyệt, ngoại trừ trình duyệt IE6 trở xuống. Thuộc tínhCách sử dụng: <abbr thuoctinh="giatri"></abbr> Thuộc tính tổng quát (xem thêm)
Thuộc tính sự kiệnKhông được hỗ trợ trong DTD Strict
This list includes the core php.ini directives you can set to configure your PHP setup. Directives handled by extensions are listed and detailed at the extension documentation pages respectively; Information on the session directives for example can be found at the sessions page.
Language OptionsLanguage and Misc Configuration Options
Here's a short explanation of the configuration directives. short_open_tag bool Tells PHP whether the short form (
precision int The number of significant digits displayed in floating point numbers. -1 means that an enhanced algorithm for rounding such numbers will be used. serialize_precision int The number of significant digits stored while serializing
floating point numbers. -1 means that an enhanced algorithm for rounding such numbers will be used. expose_php boolExposes to the world that PHP is installed on the server, which includes the PHP version within the HTTP header (e.g., X-Powered-By: PHP/5.3.7). disable_functions stringThis directive allows you to disable certain functions. It takes on a comma-delimited list of function names. Only internal functions can be disabled using this directive. User-defined functions are unaffected. This directive must be set in php.ini For example, you cannot set this in httpd.conf. disable_classes string This directive allows you to disable certain classes. It takes on a comma-delimited list of class names. This directive must be set in php.ini For example, you cannot set this in httpd.conf. zend.assertions int When set to 1 , assertion code will be generated and executed
(development mode). When set to 0 , assertion code will be generated but it will be skipped (not executed) at runtime. When set to -1 , assertion code will not be generated, making the assertions zero-cost (production mode).
zend.exception_string_param_max_len int The maximum length of string function arguments in stringified stack traces. Must range between "0" and "1000000" . hard_timeout intWhen the timeout set in max_execution_time has been hit, the PHP runtime will tear down resources gracefully. If something gets stuck while this happens, the hard timeout will tick for the set amount of seconds. When the hard timeout is hit, PHP will exit ungracefully. When set to 0, the hard timeout will never activate. When PHP stops from a hard timeout, it will look something like this: Fatal error: Maximum execution time of 30+2 seconds exceeded (terminated) in Unknown on line 0 zend.exception_ignore_args boolExcludes arguments from stack traces generated from exceptions. zend.multibyte boolEnables parsing of source files in multibyte encodings. Enabling zend.multibyte is required to use character encodings like SJIS, BIG5, etc that contain special characters in multibyte string data. ISO-8859-1 compatible encodings like UTF-8, EUC, etc do not require this option. Enabling zend.multibyte requires the mbstring extension to be available. zend.script_encoding stringThis value will be used unless a declare(encoding=...) directive appears at the top of the script. When ISO-8859-1 incompatible encoding is used, both zend.multibyte and zend.script_encoding must be used. Literal strings will be transliterated from zend.script_encoding to mbstring.internal_encoding, as if mb_convert_encoding() would have been called. zend.detect_unicode boolCheck for BOM (Byte Order Mark) and see if the file contains valid multibyte characters. This detection is performed before processing of __halt_compiler(). Available only in Zend Multibyte mode. zend.signal_check boolTo check for replaced signal handlers on shutdown. exit_on_timeout boolThis is an Apache1 mod_php-only directive that forces an Apache child to exit if a PHP execution timeout occurred. Such a timeout causes an internal longjmp() call in Apache1 which can leave some extensions in an inconsistent state. By terminating the process any outstanding locks or memory will be cleaned up. Resource LimitsResource Limits
Here's a short explanation of the configuration directives. memory_limit int This sets the maximum amount of memory in bytes that a script is allowed to allocate. This helps prevent poorly written scripts for eating up all available memory on a server. Note that to have no memory limit, set this directive to See also: max_execution_time. Performance TuningPerformance Tuning
Here's a short explanation of the configuration directives. realpath_cache_size intDetermines the size of the realpath cache to be used by PHP. This value should be increased on systems where PHP opens many files, to reflect the quantity of the file operations performed. The size represents the total number of bytes in the path strings stored, plus the size of the data associated with the cache entry. This means that in order to store longer paths in the cache, the cache size must be larger. This value does not directly control the number of distinct paths that can be cached. The size required for the cache entry data is system dependent. realpath_cache_ttl intDuration of time (in seconds) for which to cache realpath information for a given file or directory. For systems with rarely changing files, consider increasing the value. Data HandlingData Handling Configuration Options
Here's a short explanation of the configuration directives. arg_separator.output stringThe separator used in PHP generated URLs to separate arguments. arg_separator.input stringList of separator(s) used by PHP to parse input URLs into variables.
variables_order string Sets the order of the EGPCS ( Warning In both the CGI and FastCGI SAPIs, $_SERVER is also populated by values from the environment;
request_order stringThis directive describes the order in which PHP registers GET, POST and Cookie variables into the _REQUEST array. Registration is done from left to right, newer values override older values. If this directive is not set, variables_order is used for $_REQUEST contents. Note that the
default distribution php.ini files does not contain the auto_globals_jit boolWhen enabled, the SERVER, REQUEST, and ENV variables are created when they're first used (Just In Time) instead of when the script starts. If these variables are not used within a script, having this directive on will result in a performance gain. Warning Usage of SERVER, REQUEST, and ENV variables is checked during the compile time so using them through e.g. variable variables will not cause their initialization. register_argc_argv bool Tells PHP whether to declare the argv & argc variables (that would contain the GET information). See also command line. enable_post_data_reading bool Disabling this option causes $_POST and $_FILES not to be populated. The only way to read postdata will then be through the php://input stream wrapper. This can be useful to proxy requests or
to process the POST data in a memory efficient fashion. post_max_size int Sets max size of post data allowed. This setting also affects file upload. To upload large files, this value must be larger than upload_max_filesize. Generally speaking, memory_limit should be larger than post_max_size . When an int is used, the value is measured in bytes. Shorthand notation, as described in this FAQ, may also be used. If the size of
post data is greater than post_max_size, the $_POST and $_FILES superglobals are empty. This can be tracked in various ways, e.g. by passing the $_GET variable to the script processing the data, i.e. <form action="edit.php?processed=1"> , and then checking if $_GET['processed'] is set. Changelog for post_max_size
auto_prepend_file stringSpecifies the name of a file that is automatically parsed before the main file. The file is included as if it was called with the require function, so include_path is used. The special value auto_append_file stringSpecifies the name of a file that is automatically parsed after the main file. The file is included as if it was called with the require function, so include_path is used. The special value
default_mimetype stringBy default, PHP will output a media type using the Content-Type header. To disable this, simply set it to be empty. PHP's built-in default media type is set to text/html. default_charset string "UTF-8" is the
default value and its value is used as the default character encoding for htmlentities(), html_entity_decode() and htmlspecialchars() if the All versions of PHP will use this value as the charset within the default Content-Type header sent by PHP if the header isn't overridden by a call to header(). Setting input_encoding stringThis setting is used for multibyte modules such as mbstring and iconv. Default is empty. output_encoding stringThis setting is used for multibyte modules such as mbstring and iconv. Default is empty. internal_encoding stringThis setting is used for multibyte modules such as mbstring and iconv. Default is empty. If empty, default_charset is used. Paths and DirectoriesPaths and Directories Configuration Options
Here's a short explanation of the configuration directives. include_path stringSpecifies a list of directories where the require, include, fopen(), file(), readfile() and file_get_contents() functions look for files. The format is like the system's PATH environment variable: a list of directories separated with a colon in Unix or semicolon in Windows. PHP considers each
entry in the include path separately when looking for files to include. It will check the first path, and if it doesn't find it, check the next path, until it either locates the included file or returns with an Example #1 Unix include_path include_path=".:/php/includes" Example #2 Windows include_path include_path=".;c:\php\includes" Using a
Example #3 Unix include_path using ${USER} env variable include_path = ".:${USER}/pear/php" open_basedir stringLimit the files that can be accessed by PHP to the specified directory-tree, including the file itself. This directive is NOT affected by whether Safe Mode is turned On or Off. When a script tries to access the filesystem, for example using include, or fopen(), the location of the file is checked. When the file is outside the specified directory-tree, PHP will refuse to access it. All symbolic links are resolved, so it's not possible to avoid this restriction with a symlink. If the file doesn't exist then the symlink couldn't be resolved and the filename is compared to (a resolved) open_basedir. open_basedir can affect more than just filesystem functions; for example if The special value In httpd.conf, open_basedir can be turned off (e.g. for some virtual hosts) the same way as any other configuration directive
with " Under Windows, separate the directories with a semicolon. On all other systems, separate the directories with a colon. As an Apache module, open_basedir paths from parent directories are now automatically inherited. The restriction specified with open_basedir is a directory name, not a prefix. The default is to allow all files to be opened.
Caution doc_root stringPHP's "root directory" on the server. Only used if non-empty. If PHP was not compiled with FORCE_REDIRECT, you should set doc_root if you are running PHP as a CGI under any web server (other than IIS). The alternative is to use the cgi.force_redirect configuration below. user_ini.cache_ttl int user_ini.filename
string user_dir stringThe base name of the directory used on a user's home directory for PHP files, for example public_html . extension_dir stringIn what directory PHP should look for dynamically loadable extensions. It is recommended to specify an absolute path. See also: enable_dl, and dl(). extension stringWhich dynamically loadable extensions to load when PHP starts up. zend_extension stringName of dynamically loadable Zend extension (for example XDebug) to load when PHP starts up. cgi.check_shebang_line bool Controls whether CGI PHP checks for line starting with cgi.discard_path boolIf this is enabled, the PHP CGI binary can safely be placed outside of the web tree and people will not be able to circumvent .htaccess security. cgi.fix_pathinfo bool Provides real cgi.force_redirect boolcgi.force_redirect is necessary to provide security running PHP as a CGI under most web servers. Left undefined, PHP turns this on by default. You can turn it off at your own risk.
cgi.nph boolIf cgi.nph is enabled it will force cgi to always sent Status: 200 with every request. cgi.redirect_status_env stringIf cgi.force_redirect is turned on, and you are not running under Apache or Netscape (iPlanet) web servers, you may need to set an environment variable name that PHP will look for to know it is OK to continue execution.
Tells PHP what type of headers to use when sending HTTP response code. If it's set to 0, PHP sends a » RFC 3875 "Status:" header that is supported by Apache and other web servers. When this option is set to 1, PHP will send » RFC 2616 compliant headers. If this option is enabled, and you are running PHP in a CGI environment (e.g. PHP-FPM) you should not use standard RFC 2616 style HTTP status response headers, you should instead use their RFC 3875 equivalent e.g. instead of header("HTTP/1.0 404 Not found"); you should use header("Status: 404 Not Found"); Leave it set to 0 unless you know what you're doing. fastcgi.impersonate stringFastCGI under IIS (on WINNT based OS) supports the ability to impersonate security tokens of the calling client. This allows IIS to define the security context that the request runs under. mod_fastcgi under Apache does not currently support this feature (03/17/2002) Set to 1 if running under IIS. Default is zero. fastcgi.logging
boolTurns on SAPI logging when using FastCGI. Default is to enable logging. File UploadsFile Uploads Configuration Options
Here's a short explanation of the configuration directives. file_uploads boolWhether or not to allow HTTP file uploads. See also the upload_max_filesize, upload_tmp_dir, and post_max_size directives. upload_tmp_dir stringThe temporary directory used for storing files when doing file upload. Must be writable by whatever user PHP is running as. If not specified PHP will use the system's default. If the directory specified here is not writable, PHP falls back to the system default temporary directory. If open_basedir is on, then the system default directory must be allowed for an upload to succeed. upload_max_filesize intThe maximum size of an uploaded file. post_max_size must be larger than this value. When an int is used, the value is measured in bytes. Shorthand notation, as described in this FAQ, may also be used.max_file_uploads intThe maximum number of files allowed to be uploaded simultaneously. Upload fields left blank on submission do not count towards this limit. General SQLGeneral SQL Configuration Options
Here's a short explanation of the configuration directives. sql.safe_mode boolIf turned on, database connection functions that specify default values will use those values in place of any user-supplied arguments. For details on the default values, see the documentation for the relevant connection functions. Warning This feature has been REMOVED as of PHP 7.2.0. Windows SpecificWindows Specific Configuration Options
Here's a short explanation of the configuration directives. windows.show_crt_warning boolThis directive shows the Windows CRT warnings when enabled. csg at DEL_THISdiatom dot de ¶ 17 years ago
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