Php truncation of the content of an article with an html string

A blogger writes an article. The blog background usually provides the article title and truncated article part on the search page or list page as the entrance for further reading.

Function: mb_substr ($ str, $ start, $ length, $ encoding)

$ Str: string to be truncated
$ Start: truncation start
$ Length, length (note: This is different from mb_strimwidth. 1 represents a Chinese character)
$ Encoding, encoding, I set it to UTF-8

For example, the title of an article is truncated and 15 characters are allowed.

The code is as follows:	Copy code
<? Php echo mb_substr ('www .111cn.net original', 0, 15, "UTF-8");?>

In this way, there is no problem with plain text, but my problem is that there are html tags in the middle. How to cut an article. Note: this article not only contains common string text, but also contains various texts that format tags and style content. If not properly handled, these closed tags cannot be properly closed, thus damaging the entire document flow.

If it is plain text, the following function is almost enough.

  

The code is as follows:

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<? Php /** * String truncation, supporting Chinese and other encoding      * * @ Param string $ str string to be converted * @ Param string $ start position * @ Param string $ length truncation length * @ Param string $ charset encoding format * @ Param string $ suffix truncation string suffix * @ Return string */ Function substr_ext ($ str, $ start = 0, $ length, $ charset = "UTF-8", $ suffix = "")     { If (function_exists ("mb_substr ")){ Return mb_substr ($ str, $ start, $ length, $ charset). $ suffix;     } Elseif (function_exists ('iconv _ substr ')){ Return iconv_substr ($ str, $ start, $ length, $ charset). $ suffix;         } $ Re ['utf-8'] = "/[x01-x7f] | [xc2-xdf] [x80-xbf] | [xe0-xef] [x80-xbf] {2} | [xf0-xff] [x80-xbf] {3 }/"; $ Re ['gb2312'] = "/[x01-x7f] | [xb0-xf7] [xa0-xfe]/"; $ Re ['gbk'] = "/[x01-x7f] | [x81-xfe] [x40-xfe]/"; $ Re ['big5'] = "/[x01-x7f] | [x81-xfe] ([x40-x7e] | xa1-xfe])/"; Preg_match_all ($ re [$ charset], $ str, $ match ); $ Slice = join ("", array_slice ($ match [0], $ start, $ length )); Return $ slice. $ suffix;     }

However, if you want to truncate a part of the formatted text in a webpage, the above functions are not enough. It does not support formatting tags.

In this case, a new function is required. It should be the upgraded enhanced version of the above function. It must be able to process tags correctly.

The strip_tags () function removes tags from HTML, XML, and PHP.

Example 1

The code is as follows:	Copy code
<? Php Echo strip_tags ("Hello <B> world! </B> "); ?>

Output:

Hello world!

In this way, we only need to perform the following operations on the basis of the above.

The code is as follows:	Copy code
<? Php $ A = strip_tags ("Hello <B> world! </B> "); Substr_ext ($ a, 10 ); However, it is not a good solution if html is lost. ?>

Then google found that the system wrote a function that supports html string truncation.

The code is as follows:

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/** * Obtain the nth occurrence position of a character in the string. * @ Param string $ text string * @ Param string $ key * @ Param int $ int N * @ Return int */ Function strpos_int ($ text, $ key, $ int) { $ Keylen = strlen ($ key ); Global $ textlen; If (! $ Textlen) $ Textlen = strlen ($ text ); Static $ textpos = 0; $ Pos = strpos ($ text, $ key ); $ Int --; If ($ pos)     { If ($ int = 0) $ Textpos + = $ pos; Else $ Textpos + = $ pos + $ keylen;     } Else     { $ Int = 0; $ Textpos = $ textlen;     } If ($ int> 0)     { Strpos_int (substr ($ text, $ pos + $ keylen), $ key, $ int );     } Return $ textpos; }   /** * Intercept HTML * @ Param string $ string HTML string * @ Param int $ length: the length of the clip. * @ Param string $ dot * @ Param string $ append * @ Return string */ Function cuthtml ($ string, $ length, $ dot = '...', $ append = "") { $ Str = strip_tags ($ string); // filter tags first $ New_str = iconv_substr ($ str, 0, $ length, 'utf-8 '); $ Last = iconv_substr ($ new_str,-1, 1, 'utf-8 '); $ SC = substr_count ($ new_str, $ last ); $ Position = strpos_int ($ string, $ last, $ SC); // Obtain the extract length. If (function_exists ('tidy _ parse_string ') // if tidy is enabled on the server, the html code of the function is incomplete.     { $ Options = array ("show-body-only" => true ); Return tidy_parse_string (mb_substr ($ string, 0, $ position). $ dot. $ append, $ options, 'utf8 '); } Else // tidy is not enabled     { If (strlen ($ string) <= $ position)         { Return $ string;         } $ Pre = chr (1 ); $ End = chr (1 ); $ String = str_replace (array ('&', '"', '<', '>'), array ($ pre. '&'. $ end, $ pre. '"'. $ end, $ pre. '<'. $ end, $ pre. '> '. $ end), $ string ); $ Strcut = ''; $ N = $ tn = $ noc = 0; While ($ n <strlen ($ string ))         { $ T = ord ($ string [$ n]); If ($ t = 9 | $ t = 10 | (32 <= $ t & $ t <= 126 ))             { $ Tn = 1; $ N ++; $ Noc ++; } Elseif (194 <=$ t & $ t <= 223)             { $ Tn = 2; $ N + = 2; $ Noc + = 2; } Elseif (224 <=$ t & $ t <= 239)             { $ Tn = 3; $ N + = 3; $ Noc + = 2; } Elseif (240 <=$ t & $ t <= 247)             { $ Tn = 4; $ N + = 4; $ Noc + = 2; } Elseif (248 <=$ t & $ t <= 251)             { $ Tn = 5; $ N + = 5; $ Noc + = 2; } Elseif ($ t = 252 | $ t = 253)             { $ Tn = 6; $ N + = 6; $ Noc + = 2; } Else             { $ N ++;             } If ($ noc >=$ position)             { Break;             }         } If ($ noc> $ position)         { $ N-= $ tn;         } $ Strcut = substr ($ string, 0, $ n ); $ Strcut = str_replace (array ($ pre. '&'. $ end, $ pre. '"'. $ end, $ pre. '<'. $ end, $ pre. '> '. $ end), array ('&', '"', '<', '>'), $ strcut ); $ Pos = strrpos ($ strcut, chr (1 )); If ($ pos! = False)         { $ Strcut = substr ($ strcut, 0, $ pos );         } Return $ strcut. $ dot. $ append;     } }