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Title: php去除html标识截取字符串 [Print]
Author: admin    Time: 2011-11-22 12:11
Title: php去除html标识截取字符串
最近需要在HTML的内容中提取一段文本作为简介，如果用普通的办法提取那么将有可能出现截取了半个HTML标志的情况，会破坏页面布局， 为此添加了这么一个函数，可完美解决此问题！！注意在这里你截取的字符数是不含HTML标志的！！
  1. <?php   
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  2. /**  
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  3. * 截取HTML字符串 允许忽略HTML标志不计  
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  4. *  
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  5. * Author：学无止境  
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  6. * Email：xjtdy888@163.com  $ M9 R  ~$ ?9 X; F/ G; m2 h
  7. * QQ: 339534039  2 v8 @* u; |4 V+ S9 T
  8. * Home:http://www.phpos.org  4 P9 S$ O% @: M# r- _& c) q
  9. * Blog:http://hi.baidu.com/phps  
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  10. *  ) @0 G) z/ I+ Y! j6 G, L' r2 p7 |
  11. * 转载请保留作者信息  / L' u3 A/ d% f6 g0 V

  12. . z8 M2 U0 V$ G" X' \2 v
  13. *   5 J; h7 j* A2 T3 A1 k
  14. * @param 要截取的HTML $str  : |. }* o% p  n. `
  15. * @param 截取的数量 $num  9 \8 k1 H, [; P, M
  16. * @param 是否需要加上更多 $more  
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  17. * @return 截取串  
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  18. */  " X" L* U1 _- q6 J
  19. function phpos_chsubstr_ahtml($str,$num,$more=false)   
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  20. {   4 W' {, w3 ^% d# b$ ^1 n' c
  21.     $leng=strlen($str);   ! L, Z3 P/ K* Y4 ^
  22.       if($num>=$leng)      return $str;   
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  23.     $word=0;   
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  24.     $i=0;                        /** 字符串指针 **/  
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  25.     $stag=array(array());        /** 存放开始HTML的标志 **/  
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  26.     $etag=array(array());        /** 存放结束HTML的标志 **/  * l* j2 l$ q. `& F
  27.     $sp = 0;   + c; s+ d* z! V8 }6 C
  28.     $ep = 0;   
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  29.       while($word!=$num)   
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  30.       {   3 N  r/ v4 l, A; {) j0 W, ~
  31.   " d; O8 e$ g& A/ W: H, ]
  32.           if(ord($str[$i])>128)   % L0 ~: S8 M+ T' b7 S* l; p
  33.           {   7 o3 M' G! p& |5 V+ i+ b
  34.             //$re.=substr($str,$i,3);   ! F$ a# A) L* @5 y
  35.             $i+=3;   4 w! s& T. v9 R# M& H- v$ J, p
  36.             $word++;   
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  37.           }   
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  38.           else if ($str[$i]=='<')   9 Y% y+ k, o0 I" V2 @; i. h$ [
  39.           {   ' R  r# |3 r$ M, f9 t
  40.               if ($str[$i+1] == '!')   
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  41.               {   
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  42.                 $i++;   
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  43.                   continue;   8 v( D" {" G! v
  44.               }   
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  45.   
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  46.               if ($str[$i+1]=='/')       1 H$ w; @0 `, p1 g
  47.               {   
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  48.                 $ptag=$etag ;   7 z, t/ p, `- n) {
  49.                 $k=$ep;   
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  50.                 $i+=2;   
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  51.               }   , A1 ?' B. ?2 ]; E' L. k
  52.               else                       ' _0 y9 u; `: f
  53.               {   
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  54.                 $ptag=$stag;   4 V- i2 W7 b+ H( a+ C% l3 [8 R
  55.                 $i+=1;   $ i, i6 H, b5 N7 C% ~- O  \8 p$ c
  56.                 $k=$sp;   
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  57.               }   0 ^7 ?5 H! y* i' L& d! v
  58.   ( V( Y* L- |2 Z- T
  59.               for(;$i<$leng;$i++)           5 m, F$ ~% `/ Z5 K1 b8 ?! l- v
  60.               {   
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  61.                   if ($str[$i] == ' ')   
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  62.                   {   
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  63.                     $ptag[$k] = implode('',$ptag[$k]);   
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  64.                     $k++;   
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  65.                       break;   3 s! H5 ]: X$ @3 T
  66.                   }   9 U1 c& Z5 r1 n
  67.                   if ($str[$i] != '>')   
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  68.                   {   
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  69.                     $ptag[$k][]=$str[$i];   
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  70.                       continue;     ^9 {2 J/ k8 Z
  71.                   }   ( e8 g% \) t) e# W3 l$ T: ]9 K
  72.                   else                   2 l0 ?9 Y9 ~: Q2 s% j) `; [8 ^
  73.                   {   
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  74.                     $ptag[$k] = implode('',$ptag[$k]);   ( v' N# t# U, G( y$ H
  75.                     $k++;   5 l3 T. d* f2 T/ r2 d
  76.                       break;   " E/ L$ k) q# m* p! \* `) b
  77.                   }   
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  78.               }   ' O1 ^3 n2 B, Y# N  q% d- i" n
  79.             $i++;   * m! G+ u4 S$ a
  80.               continue;   
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  81.           }   
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  82.           else  4 e' K9 ]3 m2 R* q% W, |
  83.           {   
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  84.             //$re.=substr($str,$i,1);   * Z' w7 L9 I5 |+ b' d0 U9 P
  85.             $word++;   
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  86.             $i++;   , `+ s+ R1 K' O0 W6 |
  87.           }   
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  88.       }   7 x! C! R6 y8 T# x9 X: ?
  89.       foreach ($etag as $val)   ( R% B# V) [6 U8 Z
  90.       {   * w) H9 j! T# C2 t5 k
  91.         $key1=array_search($val,$stag);   $ w2 C+ ]( B1 m
  92.           if ($key1 !== false)          unset($stag[$key]);   
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  93.       }   
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  94.       foreach ($stag as $key => $val)   " ]8 }* i& b% j, M. t# ?
  95.       {   
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  96.           if (in_array($val,array('br','img'))) unset($stag[$key1]);   
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  97.       }   
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  98.     array_reverse($stag);   * ^* z' Z2 t2 b$ q
  99.     $ends = '</'.implode('></',$stag).'>';   . ~2 p) c8 ^, b: m* J; ~5 k
  100.     $re = substr($str,0,$i).$ends;   1 l/ J! n# ^# q) u& u
  101.       if($more)    $re.='...';   
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  102.       return $re;   8 B& q/ b7 Z, h) ]: Q' K; A1 U) ~3 I
  103. }   / [- A6 @7 _2 Z# J
  104.   4 G/ Z3 w% N1 F/ Y+ g: S
  105. $str=<<<EOF   
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  106. <h3>What is the <acronym>GNU</acronym> pr<a><a><a>oject?</h3>   
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  107. <p>The <acronym>GNU</acronym> Project was launched in 1984 to develop a complete Unix-like operating system which is <a href="http://www.gnu.org/philosophy/free-sw.html">free software</a>: the <acronym>GNU</acronym> system. Variants of the <acronym>GNU</acronym> operating system, which use the kernel called Linux, are now widely used; though these systems are often referred to as “Linux”, they are more accurately called <a href="http://www.gnu.org/gnu/linux-and-gnu.html">GNU/Linux systems</a>. </p>   
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  108. <p><acronym>GNU</acronym> is a recursive acronym for “GNU's Not Unix”; it is pronounced <em>guh-noo</em>, approximately like <em>canoe</em>.</p>  
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  109. <h3>What is Free Software?</h3>  
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  110. <p>“<a href="http://www.gnu.org/philosophy/free-sw.html">Free software</a>” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech”, not as in “free beer”.</p>  
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  111. <p>Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it refers to four kinds of freedom, for the users of the software:</p>   
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  112. <ul>   
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  113.       <li>The freedom to run the program, for any purpose (freedom 0). </li>   9 x8 L( W5 c- i
  114.       <li>The freedom to study how the program works, and adapt it to your needs (freedom 1). Access to the source code is a precondition for this. </li>   
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  115.       <li>The freedom to redistribute copies so you can help your neighbor (freedom 2). </li>   
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  116.       <li>The freedom to improve the program, and release your improvements to the public, so that the whole community benefits (freedom 3). Access to the source code is a precondition for this. </li>   ! r/ v9 c. G. ^$ I1 O
  117. </ul>   , l7 e  ]5 B% K5 X1 T) K
  118. <h3>What is the Free Software Foundation?</h3>   ; \% U0 o  G( d1 M
  119. <p>The <a href="http://www.fsf.org/">Free Software Foundation</a> (<abbr title="Free Software Foundation">) is the principal organizational sponsor of the Project. The receives very little funding from corporations or grant-making foundations, but relies on support from individuals like you. </abbr>) is the principal organizational sponsor of the Project. The receives very little funding from corporations or grant-making foundations, but relies on support from individuals like you. </p>   2 L- t; W8 d9 v7 c) p% V
  120. <p>Please consider helping the <abbr>by , or by . If you use Free Software in your business, you can also consider or as a way to support the . </abbr>by , or by . If you use Free Software in your business, you can also consider or as a way to support the . </p>   , W& i9 b8 X; F7 \! D. p) y" @/ I1 [
  121. <p>The <acronym>GNU</acronym> project supports the mission of the <abbr>to preserve, protect and promote the freedom to use, study, copy, modify, and redistribute computer software, and to defend the rights of Free Software users. We support the on the Internet, , and the unimpeded by private monopolies. You can also learn more about these issues in the book . </abbr>to preserve, protect and promote the freedom to use, study, copy, modify, and redistribute computer software, and to defend the rights of Free Software users. We support the on the Internet, , and the unimpeded by private monopolies. You can also learn more about these issues in the book . </p>     u. Q' `- {. h$ K: r
  122. <!--   : b& t4 y' W2 A
  123. Keep link lines at 72 characters or lynx will break them poorly   & B( _5 Q5 X- |; U
  124. Obviously, we list ONLY the most useful/important URLs here   8 ]4 F) _6 A* e6 l
  125. Keep it short and sweet: 3 lines and 2 columns is already enough   
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  126. --><!-- BEGIN GNUmenu -->   
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  127. EOF;   
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  128. echo phpos_chsubstr_ahtml($str,800);   ! [- y9 f( Q6 G# Q+ i9 J8 h. Y
  129. ?>   
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