看这些例子，压缩HTML输出的效果几乎微不足道。想一想：压缩对于使用许多重复变量和函数名称的Javascript非常适用，因为压缩的主要作用是缩短它们以及所有对它们的引用。
另一方面，HTML标记没有变量或函数的概念。页面的大部分重量都来自实际标记和内容。这无法被压缩。即使表单变量也需要保持原样，因为它们必须具有原始值才能被服务器正确处理。
Gzip已经可以非常高效地压缩空格。在HTML中，这确实是唯一能做的事情。
此外，压缩PHP没有任何应用，因为虽然它有变量和函数，但它永远不会发送给客户端。缩短名称对于在服务器上编译的东西没有性能优势。
如果你决定压缩你的HTML，请查看WordPress插件的源代码。这就是开源的美妙之处。然而，我怀疑与Gzip相比，收益将微不足道。
Peter Anselmo将代码缩小与混淆代码混淆了。在代码混淆中，代码被缩小，并且变量被重命名为最短的任意名称。缩小仅仅是减少代码大小的做法，例如删除空格，而不改变代码的值、名称或语法。
Peter Anselmo还错误地认为缩小标记会导致无关紧要的节省。例如，这个页面显示了18.31%的节省，而且它本来就很整洁。显然，他在发表意见之前从未测试过。您可以使用Pretty Diff工具自己查看成本节省情况：http://prettydiff.com/
您可以尝试反向工程化用于执行PHP的缩小引擎。该代码和配套文档可在prettydiff.com/markupmin.js找到。
echo format::minify_html($html_output);
以下是代码（目前还在beta测试阶段，但是目前还没有出现很多问题）
<?php
class format(){
static function minify_css($text){
$from = array(
// '%(#|;|(//)).*%', // comments: # or //
'%/\*(?:(?!\*/).)*\*/%s', // comments: /*...*/
'/\s{2,}/', // extra spaces
"/\s*([;{}])[\r\n\t\s]/", // new lines
'/\\s*;\\s*/', // white space (ws) between ;
'/\\s*{\\s*/', // remove ws around {
'/;?\\s*}\\s*/', // remove ws around } and last semicolon in declaration block
// '/:first-l(etter|ine)\\{/', // prevent triggering IE6 bug: http://www.crankygeek.com/ie6pebug/
// '/((?:padding|margin|border|outline):\\d+(?:px|em)?) # 1 = prop : 1st numeric value\\s+/x', // Use newline after 1st numeric value (to limit line lengths).
// '/([^=])#([a-f\\d])\\2([a-f\\d])\\3([a-f\\d])\\4([\\s;\\}])/i',
);
$to = array(
// '',
'',
' ',
'$1',
';',
'{',
'}',
// ':first-l$1 {',
// "$1\n",
// '$1#$2$3$4$5',
);
$text = preg_replace($from,$to,$text);
return $text;
}
static function minify_js($text){
$file_cache = strtolower(md5($text));
$folder = TMPPATH.'tmp_files'.DIRECTORY_SEPARATOR.substr($file_cache,0,2).DIRECTORY_SEPARATOR;
if(!is_dir($folder)) @mkdir($folder, 0766, true);
if(!is_dir($folder)){
echo 'Impossible to create the cache folder:'.$folder;
return 1;
}
$file_cache = $folder.$file_cache.'_content.js';
if(!file_exists($file_cache)){
if(strlen($text)<=100){
$contents = $text;
} else {
$contents = '';
$post_text = http_build_query(array(
'js_code' => $text,
'output_info' => 'compiled_code',//($returnErrors ? 'errors' : 'compiled_code'),
'output_format' => 'text',
'compilation_level' => 'SIMPLE_OPTIMIZATIONS',//'ADVANCED_OPTIMIZATIONS',//'SIMPLE_OPTIMIZATIONS'
), null, '&');
$URL = 'http://closure-compiler.appspot.com/compile';
$allowUrlFopen = preg_match('/1|yes|on|true/i', ini_get('allow_url_fopen'));
if($allowUrlFopen){
$contents = file_get_contents($URL, false, stream_context_create(array(
'http' => array(
'method' => 'POST',
'header' => 'Content-type: application/x-www-form-urlencoded',
'content' => $post_text,
'max_redirects' => 0,
'timeout' => 15,
)
)));
}elseif(defined('CURLOPT_POST')) {
$ch = curl_init($URL);
curl_setopt($ch, CURLOPT_POST, true);
curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
curl_setopt($ch, CURLOPT_HTTPHEADER, array('Content-type: application/x-www-form-urlencoded'));
curl_setopt($ch, CURLOPT_POSTFIELDS, $post_text);
curl_setopt($ch, CURLOPT_FOLLOWLOCATION, false);
curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 15);
$contents = curl_exec($ch);
curl_close($ch);
} else {
//"Could not make HTTP request: allow_url_open is false and cURL not available"
$contents = $text;
}
if($contents==false || (trim($contents)=='' && $text!='') || strtolower(substr(trim($contents),0,5))=='error' || strlen($contents)<=50){
//No HTTP response from server or empty response or error
$contents = $text;
}
}
if(trim($contents)!=''){
$contents = trim($contents);
$f = fopen($file_cache, 'w');
fwrite($f, $contents);
fclose($f);
}
} else {
touch($file_cache); //in the future I will add a timetout to the cache
$contents = file_get_contents($file_cache);
}
return $contents;
}
static function minify_html($text){
if(isset($_GET['no_mini'])){
return $text;
}
$file_cache = strtolower(md5($text));
$folder = TMPPATH.'tmp_files'.DIRECTORY_SEPARATOR.substr($file_cache,0,2).DIRECTORY_SEPARATOR;
if(!is_dir($folder)) @mkdir($folder, 0766, true);
if(!is_dir($folder)){
echo 'Impossible to create the cache folder:'.$folder;
return 1;
}
$file_cache = $folder.$file_cache.'_content.html';
if(!file_exists($file_cache)){
//get CSS and save it
$search_css = '/<\s*style\b[^>]*>(.*?)<\s*\/style>/is';
$ret = preg_match_all($search_css, $text, $tmps);
$t_css = array();
if($ret!==false && $ret>0){
foreach($tmps as $k=>$v){
if($k>0){
foreach($v as $kk=>$vv){
$t_css[] = $vv;
}
}
}
}
$css = format::minify_css(implode('\n', $t_css));
/*
//get external JS and save it
$search_js_ext = '/<\s*script\b.*?src=\s*[\'|"]([^\'|"]*)[^>]*>\s*<\s*\/script>/i';
$ret = preg_match_all($search_js_ext, $text, $tmps);
$t_js = array();
if($ret!==false && $ret>0){
foreach($tmps as $k=>$v){
if($k>0){
foreach($v as $kk=>$vv){
$t_js[] = $vv;
}
}
}
}
$js_ext = $t_js;
*/
//get inline JS and save it
$search_js_ext = '/<\s*script\b.*?src=\s*[\'|"]([^\'|"]*)[^>]*>\s*<\s*\/script>/i';
$search_js = '/<\s*script\b[^>]*>(.*?)<\s*\/script>/is';
$ret = preg_match_all($search_js, $text, $tmps);
$t_js = array();
$js_ext = array();
if($ret!==false && $ret>0){
foreach($tmps as $k=>$v){
if($k==0){
//let's check if we have a souce (src="")
foreach($v as $kk=>$vv){
if($vv!=''){
$ret = preg_match_all($search_js_ext, $vv, $ttmps);
if($ret!==false && $ret>0){
foreach($ttmps[1] as $kkk=>$vvv){
$js_ext[] = $vvv;
}
}
}
}
} else {
foreach($v as $kk=>$vv){
if($vv!=''){
$t_js[] = $vv;
}
}
}
}
}
$js = format::minify_js(implode('\n', $t_js));
//get inline noscript and save it
$search_no_js = '/<\s*noscript\b[^>]*>(.*?)<\s*\/noscript>/is';
$ret = preg_match_all($search_no_js, $text, $tmps);
$t_js = array();
if($ret!==false && $ret>0){
foreach($tmps as $k=>$v){
if($k>0){
foreach($v as $kk=>$vv){
$t_js[] = $vv;
}
}
}
}
$no_js = implode('\n', $t_js);
//remove CSS and JS
$search = array(
$search_js_ext,
$search_css,
$search_js,
$search_no_js,
'/\>[^\S ]+/s', //strip whitespaces after tags, except space
'/[^\S ]+\</s', //strip whitespaces before tags, except space
'/(\s)+/s', // shorten multiple whitespace sequences
);
$replace = array(
'',
'',
'',
'',
'>',
'<',
'\\1',
);
$buffer = preg_replace($search, $replace, $text);
$append = '';
//add CSS and JS at the bottom
if(is_array($js_ext) && count($js_ext)>0){
foreach($js_ext as $k=>$v){
$append .= '<script type="text/javascript" language="javascript" src="'.$v.'" ></script>';
}
}
if($css!='') $append .= '<style>'.$css.'</style>';
if($js!=''){
//remove weird '\n' strings
$js = preg_replace('/[\s]*\\\n/', "\n", $js);
$append .= '<script>'.$js.'</script>';
}
if($no_js!='') $append .= '<noscript>'.$no_js.'</noscript>';
$buffer = preg_replace('/(.*)(<\s*\/\s*body\s*>)(.*)/','\\1'.$append.'\\2\\3', $buffer);
if(trim($buffer)!=''){
$f = fopen($file_cache, 'w');
fwrite($f, trim($buffer));
fclose($f);
}
} else {
touch($file_cache); //in the future I will add a timetout to the cache
$buffer = file_get_contents($file_cache);
}
return $buffer;
}
}
?>