PHP Trim html output of a html page

PHP-Trim-output.php

<?php

/**
 * Trim output of html
 */
function trim_output($buffer)
{
    // Replace key with their values.
    $replace = array(
        "#<!--.*?-->#s"                 => "",      // strip comments
        "#>\s+<#"                       => ">\n<",  // strip excess whitespace
        "#\n\s+<#"                      => "\n<",   // strip excess whitespace
        '!/\*[^*]*\*+([^/][^*]*\*+)*/!' => '',      // Strip css comments
        '![ \t]*//.*[ \t]*[\r\n]!'      =>  '',     // Removes single line '//' comments, treats blank characters
        '~>\s*\n\s*<~'                  => '><',    // Remove extra space between HTML tags
    );

    // Take keys as search parameter.
    $search = array_keys($replace);

    // Now replace the buffer (html output) 
    $buffer = preg_replace($search, $replace, $buffer);

    // Return trimmed output buffer
    return $buffer;
}

ob_start('trim_output'); // Trim html output (put this code in config of your web application)