php截取html字符串自动补全html标签

文章来总结一下关于利用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:

<?php
/**
 * 截取HTML,并自动补全闭合
 * @param $html
 * @param $length
 * @param $end
 */
function subHtml($html, $length) {
    $result = &#39;&#39;;
    $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) == "") & nbsp;
        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)) {
        $result.= &#39;</&#39; . array_pop($tagStack) . &#39;>&#39;;
    }
    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 = &#39;&#39;, $charset = &#39;UTF-8&#39;) {
    $string = str_replace(array(
        &#39;&&#39;,
        &#39;"&#39;,
        &#39;<&#39;,
        &#39;>&#39;,
        &#39; &#39;
    ) , array(
        &#39;&&#39;,
        &#39;"&#39;,
        &#39;<&#39;,
        &#39;>&#39;,
        &#39; &#39;
    ) , $string);
    if (strlen($string) <= $length) {
        return $string;
    }
    if (strtolower($charset) == &#39;utf-8&#39;) {
        $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 = &#39;UTF-8&#39;) {
    if (function_exists(&#39;mb_substr&#39;)) {
        $length = mb_strlen($str, $charset);
    } elseif (function_exists(&#39;iconv_substr&#39;)) {
        $length = iconv_strlen($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); & nbsp;
        $length = count($ar[0]);
    }
    return $length;
}
?>

实例,代码如下:

<?php
/*
* @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
*/
$leng = strlen($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[$i] == &#39;<&#39;) {
            if ($str[$i + 1] == &#39;!&#39;) {
                $i++;
                continue;
            }
            if ($str[$i + 1] == &#39;/&#39;) {
                $ptag = & $etag;
                $k = & $ep;
                $i+= 2;
            } else {
                $ptag = & $stag;
                $i+= 1;
                $k = & $sp;
            }
            for (; $i < $leng; $i++) {
                if ($str[$i] == &#39; &#39;) {
                    $ptag[$k] = implode(&#39;&#39;, $ptag[$k]);
                    $k++;
                    break;
                }
                if ($str[$i] != &#39;>&#39;) {
                    $ptag[$k][] = $str[$i];
                    continue;
                } else {
                    $ptag[$k] = implode(&#39;&#39;, $ptag[$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(
            &#39;br&#39;,
            &#39;img&#39;
        ))) unset($stag[$key1]);
    }
    array_reverse($stag);
    $ends = &#39;</&#39; . implode(&#39;></&#39;, $stag) . &#39;>&#39;;
    $re = substr($str, 0, $i) . $ends;
    if ($more) $re.= &#39;...&#39;;
    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:

<?php
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, $re, &#39;i&#39;);
    while ($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;
            }
?>

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