This » PECL extension is not bundled with PHP. Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » http://pecl.php.net/package/domxml.
In PHP 4 this PECL extensions source can be found in the ext/ directory within the PHP source or at the PECL link above. This extension is only available if PHP was configured with --with-dom[=DIR]. Add --with-dom-xslt[=DIR] to include DOM XSLT support. DIR is the libxslt install directory. Add --with-dom-exslt[=DIR] to include DOM EXSLT support, where DIR is the libexslt install directory.
Windows users will enable php_domxml.dll inside of php.ini in order to use these functions. In PHP 4 this DLL resides in the extensions/ directory within the PHP Windows binaries download. The DLL for this PECL extension may be downloaded from either the » PHP Downloads page or from » http://pecl4win.php.net/ Also, there is one additional DLL that must be made available to your system's PATH in order for this extension to work. In PHP 4 this is in the dlls/ directory. It's name: For PHP <= 4.2.0, it's libxml2.dll. For PHP >= 4.3.0, it's iconv.dll. And as of PHP 5.0.0, iconv is compiled into your Windows PHP binaries by default so no extra DLL is needed.