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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  3 U, G+ P+ \+ b  E+ f1 L
  4. *  / I) n9 {: D+ U4 W. P6 m, ~! R6 B& q
  5. * Author：学无止境  
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  6. * Email：xjtdy888@163.com  
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  7. * QQ: 339534039  3 G' E( O1 j2 D
  8. * Home:http://www.phpos.org  ( H4 X" i/ N0 h1 Z' A
  9. * Blog:http://hi.baidu.com/phps  $ W. y' q* k- {% u
  10. *  . C+ y4 z% ?8 g" d: E
  11. * 转载请保留作者信息  
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  12. 4 C( d6 q- I8 W! x3 j
  13. *   
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  14. * @param 要截取的HTML $str  
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  15. * @param 截取的数量 $num  
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  16. * @param 是否需要加上更多 $more  
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  17. * @return 截取串  
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  18. */  5 S6 Z  P4 V" q
  19. function phpos_chsubstr_ahtml($str,$num,$more=false)   
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  20. {   
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  21.     $leng=strlen($str);   $ w. X# W# m2 X  ~' g: e4 M7 ?0 k0 I* V
  22.       if($num>=$leng)      return $str;   
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  23.     $word=0;   ' J  @* Y: B. ^% I4 I! t
  24.     $i=0;                        /** 字符串指针 **/  
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  25.     $stag=array(array());        /** 存放开始HTML的标志 **/  ! i" i7 f* p* I4 S, X
  26.     $etag=array(array());        /** 存放结束HTML的标志 **/  8 J6 U  w1 j, I3 S
  27.     $sp = 0;   
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  28.     $ep = 0;   8 H5 p$ U+ y7 d1 m% n
  29.       while($word!=$num)   
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  30.       {   ( j: f6 k; `8 @1 K# r
  31.   
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  32.           if(ord($str[$i])>128)   
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  33.           {   
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  34.             //$re.=substr($str,$i,3);   ' [# o. F5 Q% J- ^  m6 \/ h& ?8 z
  35.             $i+=3;   / }! n5 a9 m2 |: Y/ R2 Q
  36.             $word++;   
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  37.           }   
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  38.           else if ($str[$i]=='<')   
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  39.           {   " b2 T3 H3 B# v( S
  40.               if ($str[$i+1] == '!')   : i$ i9 ?# j, B' I$ k+ b( I$ n4 a
  41.               {   
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  42.                 $i++;   
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  43.                   continue;   # X/ ]2 d& y( D( v1 G7 }( T
  44.               }   
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  45.   + x, j+ T1 B. f3 }! K
  46.               if ($str[$i+1]=='/')       0 I. ?2 G/ B8 {6 p
  47.               {   * \; K2 ?( W* T! T+ z/ S3 a7 F3 n
  48.                 $ptag=$etag ;   # M) o. Z) s6 `7 b* G
  49.                 $k=$ep;   0 l; y* n7 n/ F
  50.                 $i+=2;   , ?& Q- d2 w9 u8 I9 r
  51.               }   & @; V9 @/ ~: p
  52.               else                       
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  53.               {     J3 d0 ]4 Z6 L" c' l. `' k; Z: O
  54.                 $ptag=$stag;   5 t. G! ]$ b% [6 z
  55.                 $i+=1;   
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  56.                 $k=$sp;   
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  57.               }   9 c: R" E& M6 y) k# G/ ~( n
  58.   % W. h4 G% I2 C; `
  59.               for(;$i<$leng;$i++)           
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  60.               {   + f; q1 F  J( y9 \/ F& O& M
  61.                   if ($str[$i] == ' ')   " b+ K7 e9 s# z  E" W
  62.                   {   
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  63.                     $ptag[$k] = implode('',$ptag[$k]);   1 \3 g$ w3 @( `  z
  64.                     $k++;   + @7 t5 y1 s% m$ t* @/ k5 f( ]
  65.                       break;   ) Y  g+ m2 P2 ?
  66.                   }     v* ?! k" z! F% q
  67.                   if ($str[$i] != '>')    . G' o, S5 P* q% H) A" W* Y
  68.                   {   
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  69.                     $ptag[$k][]=$str[$i];   
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  70.                       continue;   
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  71.                   }     o  Z# O& g) z
  72.                   else                   : Q2 s1 h( m! E
  73.                   {   " ?6 F/ H* M3 ^# j
  74.                     $ptag[$k] = implode('',$ptag[$k]);   
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  75.                     $k++;   
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  76.                       break;   
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  77.                   }   
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  78.               }   
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  79.             $i++;   
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  80.               continue;   
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  81.           }   " k+ n$ T/ r% p2 H
  82.           else  7 S$ [! q1 `9 T" a
  83.           {   & ~1 n, Z, B) k. V- h7 R3 w# i0 t
  84.             //$re.=substr($str,$i,1);   
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  85.             $word++;   0 u/ ]6 W2 L( _* v) I1 t. @! G
  86.             $i++;   & T  z0 v$ x0 Q" C
  87.           }   
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  88.       }   ( m6 C5 \5 o1 x* k! m& i' h+ \" I
  89.       foreach ($etag as $val)   / z& D% d+ n$ y% r# t9 t
  90.       {   
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  91.         $key1=array_search($val,$stag);   ( f+ N* _) K$ d
  92.           if ($key1 !== false)          unset($stag[$key]);   7 i' H1 z* H/ }% K* M' {: @  q
  93.       }   
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  94.       foreach ($stag as $key => $val)   0 i- a/ L. M" I  I
  95.       {   0 I! d4 G% _$ R1 J
  96.           if (in_array($val,array('br','img'))) unset($stag[$key1]);   
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  97.       }   
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  98.     array_reverse($stag);   + f! l  D* I, t% D- i  v7 t
  99.     $ends = '</'.implode('></',$stag).'>';   : K( U! `. k; ]6 h" {$ f
  100.     $re = substr($str,0,$i).$ends;   
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  101.       if($more)    $re.='...';   
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  102.       return $re;   
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  103. }   
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  104.   9 e$ f- Y& Q6 f3 Q* g) b; t8 G" W
  105. $str=<<<EOF   
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  106. <h3>What is the <acronym>GNU</acronym> pr<a><a><a>oject?</h3>   
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  107. <p>The <acronym>GNU</acronym> Project was launched in 1984 to develop a complete Unix-like operating system which is <a href="http://www.gnu.org/philosophy/free-sw.html">free software</a>: the <acronym>GNU</acronym> system. Variants of the <acronym>GNU</acronym> operating system, which use the kernel called Linux, are now widely used; though these systems are often referred to as “Linux”, they are more accurately called <a href="http://www.gnu.org/gnu/linux-and-gnu.html">GNU/Linux systems</a>. </p>   0 f2 p4 d# C2 {/ E+ ?
  108. <p><acronym>GNU</acronym> is a recursive acronym for “GNU's Not Unix”; it is pronounced <em>guh-noo</em>, approximately like <em>canoe</em>.</p>  7 @9 z# G# B2 n
  109. <h3>What is Free Software?</h3>  
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  110. <p>“<a href="http://www.gnu.org/philosophy/free-sw.html">Free software</a>” is a matter of liberty, not price. To understand the concept, you should think of “free” as in “free speech”, not as in “free beer”.</p>  6 y7 j3 N9 Y) c+ C7 L, W
  111. <p>Free software is a matter of the users' freedom to run, copy, distribute, study, change and improve the software. More precisely, it refers to four kinds of freedom, for the users of the software:</p>   9 i  C% Z' x; F' s9 s- D5 r0 o  O  p5 X
  112. <ul>   ! U$ a# y; o5 |7 a
  113.       <li>The freedom to run the program, for any purpose (freedom 0). </li>   
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  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>   7 F9 z" e. K( R# V: n2 \
  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>   
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  117. </ul>   
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  118. <h3>What is the Free Software Foundation?</h3>   
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  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>   3 u4 x7 m1 ~6 h0 z- a
  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>   
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  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>   
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  122. <!--   ( p2 c; M0 `  D( {5 c1 [' R% X
  123. Keep link lines at 72 characters or lynx will break them poorly   
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  124. Obviously, we list ONLY the most useful/important URLs here   + v+ S: P6 X" E/ U! q, y
  125. Keep it short and sweet: 3 lines and 2 columns is already enough   
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  126. --><!-- BEGIN GNUmenu -->   # j' h7 l0 ]- D
  127. EOF;   
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  128. echo phpos_chsubstr_ahtml($str,800);   
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  129. ?>   
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