php截取html字符串及自动补全html标签的方法

本文实例讲述了php截取html字符串及自动补全html标签的方法。分享给大家供大家参考。具体分析如下：

这里总结一下关于利用php截取html字符串自动补全html标签,实际开发中会经常碰到,很多人直接先strip_tags过滤掉html标签,但是就只剩下纯文本了,可读性非常差,下面是一个函数,代码如下:复制代码 代码如下:/**  * 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 .= $tag;  }  }else if(preg_match("~<([a-z0-9]+)[^/>]*?>~si",$tag,$match)){  array_push($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,0,$length-$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, 0, $n);  } else {  for($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; }实例,代码如下:复制代码 代码如下:* @param 要截取的HTML $str * @param 截取的数量 $num * @param 是否需要加上更多 $more * @return 截取串 */ function phpos_chsubstr_ahtml($str,$num,$more=false) {     $leng=strlen($str);       if($num>=$leng)      return $str;     $word=0;     $i=0;                        /** 字符串指针 **/     $stag=array(array());        /** 存放开始HTML的标志 **/     $etag=array(array());        /** 存放结束HTML的标志 **/     $sp = 0;     $ep = 0;       while($word!=$num)       {           if(ord($str[$i])>128)           {             //$re.=substr($str,$i,3);             $i+=3;             $word++;           }           else if ($str[$i]=="<")           {               if ($str[$i+1] == "!")               {                 $i++;                   continue;               }                if ($str[$i+1]=="/")                   {                 $ptag=&$etag ;                 $k=&$ep;                 $i+=2;               }               else                                   {                 $ptag=&$stag;                 $i+=1;                 $k=&$sp;               }                for(;$i<$leng;$i++)                       {                   if ($str[$i] == " ")                   {                     $ptag[$k] = implode("",$ptag[$k]);                     $k++;                       break;                   }                   if ($str[$i] != ">")                    {                     $ptag[$k][]=$str[$i];                       continue;                   }                   else                                   {                     $ptag[$k] = implode("",$ptag[$k]);                     $k++;                       break;                   }               }             $i++;               continue;           }           else           {             //$re.=substr($str,$i,1);             $word++;             $i++;           }       }       foreach ($etag as $val)       {         $key1=array_search($val,$stag);           if ($key1 !== false)          unset($stag[$key]);       }       foreach ($stag as $key => $val)       {           if (in_array($val,array("br","img"))) unset($stag[$key1]);       }     array_reverse($stag);     $ends = "</".implode("></",$stag).">";     $re = substr($str,0,$i).$ends;       if($more)    $re.="...";       return $re; }PHP截取字符串,生成文章摘要,我们在写BLOG时经常需要显示文章前一部分,但是又怕不恰当截断破坏封闭标签以造成整个文档结构破坏,代码如下:复制代码 代码如下:function text_zhaiyao($text,$length){ //文章摘要生成函数  $test:内容 $length:摘要长度     global $Briefing_Length;     mb_regex_encoding("UTF-8");     if(mb_strlen($text) <= $length ) return $text;     $Foremost = mb_substr($text, 0, $length);     $re = "<(/?)     (P|DIV|H1|H2|H3|H4|H5|H6|ADDRESS|PRE|TABLE|TR|TD|TH|INPUT|SELECT|TEXTAREA|OBJECT|A|UL|OL|LI|     BASE|META|LINK|HR|BR|PARAM|IMG|AREA|INPUT|SPAN)[^>]*(>?)";     $Single = "/BASE|META|LINK|HR|BR|PARAM|IMG|AREA|INPUT|BR/i";           $Stack = array(); $posStack = array();           mb_ereg_search_init($Foremost, $re, "i");           while($pos = mb_ereg_search_pos()){     $match = mb_ereg_search_getregs();     /* [Child-matching Formulation]:           $matche[1] : A "/" charactor indicating whether current "<...>" Friction is     Closing Part     $matche[2] : Element Name.     $matche[3] : Right > of a "<...>" Friction     */     if($match[1]==""){     $Elem = $match[2];     if(mb_eregi($Single, $Elem) && $match[3] !=""){     continue; }

希望本文所述对大家的php程序设计有所帮助。