php截取html字符串及自动补全html标签的方法

** * 截取HTML,并自动补全闭合 * @param $html * @param $length * @param $end */ function subHtml($html,$length) { $result = ''; $tagStack = array(); $len = 0;

$contents = preg_split("~(<[^>]+?>)~si",$html,-1,PREG_SPLIT_NO_EMPTY| PREG_SPLIT_DELIM_CAPTURE);
foreach($contents as $tag)
{
if (trim($tag)=="") conTinue;
if(preg_match("~<([a-z0-9]+)[^/>]?/>~si",$tag)){
$result .= $tag;
}else if(preg_match("~</([a-z0-9]+)[^/>]?>~si",$tag,$match)){
if($tagStack[count($tagStack)-1] == $match[1]){
array_pop($tagStack);
$result .= $tag;
}
}else if(preg_match("~<([a-z0-9]+)[^/>]?>~si",$match)){
array_push($tagStack,$match[1]);
$result .= $tag;
}else if(preg_match("~<!--.?-->~si",$tag)){
$result .= $tag;
}else{
if($len + mstrlen($tag) < $length){
$result .= $tag;
$len += mstrlen($tag);
}else {
$str = msubstr($tag,$length-$len+1);
$result .= $str;
break;
}

}
}
while(!emptyempty($tagStack)){
$result .= '</'.array_pop($tagStack).'>';
}
return $result;
}

/**

• 截取中文字符串
• @param $String 字符串
• @param $start 起始位
• @param $length 长度
• @param $charset 编码
• @param $dot 附加字串
  */
  function msubstr($String,$start,$length,$dot='',$charset = 'UTF-8') {
  $String = str_replace(array('&','"','<','>',''),array('&','"',' '),$String);
  if(strlen($String) <= $length) {
  return $String;
  }

if(strtolower($charset) == 'utf-8') {
$n = $tn = $noc = 0;
while($n < strlen($String)) {
$t = ord($String[$n]);
if($t == 9 || $t == 10 || (32 <= $t && $t <= 126)) {
$tn = 1; $n++;
} elseif(194 <= $t && $t <= 223) {
$tn = 2; $n += 2;
} elseif(224 <= $t && $t <= 239) {
$tn = 3; $n += 3;
} elseif(240 <= $t && $t <= 247) {
$tn = 4; $n += 4;
} elseif(248 <= $t && $t <= 251) {
$tn = 5; $n += 5;
} elseif($t == 252 || $t == 253) {
$tn = 6; $n += 6;
} else {
$n++;
}
$noc++;
if($noc >= $length) {
break;
}
}
if($noc > $length) {
$n -= $tn;
}
$strcut = substr($String,$n);
} else {
for($i = 0; $i < $length; $i++) {
$strcut .= ord($String[$i]) > 127 ? $String[$i].$String[++$i] : $String[$i];
}
}

return $strcut.$dot;
}

/**

• 取得字符串的长度，包括中英文。
  /
  function mstrlen($str,$charset = 'UTF-8'){
  if (function_exists('mb_substr')) {
  $length=mb_strlen($str,$charset);
  } elseif (function_exists('iconv_substr')) {
  $length=iconv_strlen($str,$charset);
  } else {
  preg_match_all("/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/",$text,$ar);
  $length=count($ar[0]);
  }
  return $length;
  }