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我想使用 REGEX 从 HTML 文档中获取所有链接，除了具有指定类名的链接。

例如：

<a href="someSite" class="className">qwe</a> <a href="someSite">qwe</a>

结果，我只想从不包含等于“className”的类的链接中获得href="someSite "

我创建了正则表达式：

(?<=<\s*a.*)href\s*?=\s*?("|').*?("|')

它准确地返回了我想要的东西，但是从所有链接中，我不知道如何向我的正则表达式添加一个异常，以不返回指定类名的链接

任何帮助将不胜感激 ：）

4

5 回答 5

2

如果你愿意使用 jQuery，你可以不使用 Regex 来做到这一点：

 var list = $("a", document).filter(function () {
                return $(this).hasClass("className") == false;
            });
于 2012-06-26T11:28:55.203 回答
0

假设您在某个变量中有 HTML，您可以使用http://code.google.com/p/phpquery/wiki/Selectors（phpquery - php 的 php jQuery-esq 事物）。

于 2012-06-26T11:39:11.460 回答
0

免责声明：

正如其他人将要或已经指出的那样，使用正则表达式解析非常规语言充满危险！最好使用专门为这项工作设计的专用解析器，尤其是在解析 HTML 标签汤时。

那就是说...

如果您坚持使用正则表达式，这里是一个经过测试的 PHP 脚本，它实现了一个“相当不错”的正则表达式解决方案：

<?php // test.php Rev:20120626_2100

function strip_html_anchor_tags_not_having_class($text) {
    $re_html_anchor_not_having_class ='% # Rev:20120626_1300
    # Match an HTML 4.01 A element NOT having a specific class.
    <a\b                   # Anchor element start tag open delimiter
    (?:                    # Zero or more attributes before CLASS.
      \s+                  # Attributes are separated by whitespace.
      (?!class\b)          # Only non-CLASS attributes here.
      [A-Za-z][\w\-:.]*    # Attribute name is required.
      (?:                  # Attribute value is optional.
        \s*=\s*            # Name and value separated by =
        (?:                # Group for value alternatives.
          "[^"]*"          # Either a double-quoted string,
        | \'[^\']*\'       # or a single-quoted string,
        | [\w\-:.]+        # or a non-quoted string.
        )                  # End group of value alternatives.
      )?                   # Attribute value is optional.
    )*                     # Zero or more attributes before CLASS.
    (?:                    # Optional CLASS (but only if NOT MyClass).
      \s+                  # CLASS attribute is separated by whitespace.
      class                # (case insensitive) CLASS attribute name.
      \s*=\s*              # Name and value separated by =
      (?:                  # Group allowable CLASS value alternatives.
        (?-i)              # Use case-sensitive match for CLASS value.
        "                  # Either a double-quoted value...
        (?:                # Single-char-step through CLASS value.
          (?!              # Assert each position is NOT MyClass.
            (?<=["\s])     # Preceded by opening quote or space.
            MyClass        # (case sensitive) CLASS value to NOT be matched.
            (?=["\s])      # Followed by closing quote or space.
          )                # End assert each position is NOT MyClass.
          [^"]             # Safe to match next CLASS value char.
        )*                 # Single-char-step through CLASS value.
        "                  # Ok. DQ value does not contain MyClass.
      | \'                 # Or a single-quoted value...
        (?:                # Single-char-step through CLASS value.
          (?!              # Assert each position is NOT MyClass.
            (?<=[\'\s])    # Preceded by opening quote or space.
            MyClass        # (case sensitive) CLASS value to NOT be matched.
            (?=[\'\s])     # Followed by closing quote or space.
          )                # End assert each position is NOT MyClass.
          [^\']            # Safe to match next CLASS value char.
        )*                 # Single-char-step through CLASS value.
        \'                 # Ok. SQ value does not contain MyClass.
      |                    # Or a non-quoted, non-MyClass value...
        (?!                # Assert this value is NOT MyClass.
          MyClass          # (case sensitive) CLASS value to NOT be matched.
        )                  # Ok. NQ value is not MyClass.
        [\w\-:.]+          # Safe to match non-quoted CLASS value.
      )                    # End group of allowable CLASS values.
      (?:                  # Zero or more attribs allowed after CLASS.
        \s+                # Attributes are separated by whitespace.
        [A-Za-z][\w\-:.]*  # Attribute name is required.
        (?:                # Attribute value is optional.
          \s*=\s*          # Name and value separated by =
          (?:              # Group for value alternatives.
            "[^"]*"        # Either a double-quoted string,
          | \'[^\']*\'     # or a single-quoted string,
          | [\w\-:.]+      # or a non-quoted string.
          )                # End group of value alternatives.
        )?                 # Attribute value is optional.
      )*                   # Zero or more attributes after CLASS.
    )?                     # Optional CLASS (but only if NOT MyClass).
    \s*                    # Optional whitespace before closing >
    >                      # Anchor element start tag close delimiter
    (                      # $1: Anchor element contents.
      [^<]*                # {normal*} Zero or more non-<
      (?:                  # Begin {(special normal*)*} construct
        <                  # {special} Allow a < but only if
        (?!/?a\b)          # not the start of the </a> close tag.
        [^<]*              # more {normal*} Zero or more non-<
      )*                   # Finish {(special normal*)*} construct
    )                      # End $1: Anchor element contents.
    </a\s*>                # A element close tag.
    %ix';
    // Remove all matching start and end tags but keep the element contents.
    return preg_replace($re_html_anchor_not_having_class, '$1', $text);
}
$input = file_get_contents('testdata.html');
$output = strip_html_anchor_tags_not_having_class($input);
file_put_contents('testdata_out.html', $output);
?>

function strip_html_anchor_tags_not_having_class($text)

此函数去除所有 HTML 4.01 Anchor 元素（即<A>标签）的开始和匹配结束标签，这些元素不具有特定的（区分大小写的）CLASS属性值，其中包含：MyClass。该CLASS值可以包含任意数量的值，但其中之一必须是：MyClass。Anchor 标记名称和 CLASS 属性名称不区分大小写。

示例输入 ( testdata.html)：

<h2>Paragraph contains links to be preserved (CLASS has "MyClass"):</h2>
<p>
Single DQ matching CLASS: <a href="URL" class="MyClass">Test 01</a>.
Single SQ matching CLASS: <a href="URL" class='MyClass'>Test 02</a>.
Single NQ matching CLASS: <a href="URL" class=MyClass>Test 03</a>.
Variable whitespace: <a href = "URL" class = MyClass >Test 04</a>.
Variable capitalization: <A HREF = "URL" CLASS = "MyClass" >Test 04</A>.
Reversed attribute order: <a class="MyClass" href="URL">Test 05</a>
Class before MyClass: <a href="URL" class="Pre MyClass">Test 06</a>.
Class after MyClass: <a href="URL" class="MyClass Post">Test 07</a>.
Sandwiched MyClass: <a href="URL" class="Pre MyClass Post">Test 08</a>.
Link with HTML content: <a class="MyClass" href="URL"><b>Test</b> 09</a>.
</p>

<h2>Paragraph contains links to be stripped (NO CLASS with "MyClass"):</h2>
<p>
Case does not match: <a href="URL" class="myclass">TEST 10</a>.
CLASS not whole word: <a href="URL" class="NotMyClass">TEST 11</a>.
No class attribute: <a href="URL">TEST 12</a>.
Link with HTML content: <a class="NotMyClass" href="URL"><b>Test</b> 13</a>.
</p>

示例输出 ( testdata_out.html)：

<h2>Paragraph contains links to be preserved (CLASS has "MyClass"):</h2>
<p>
Single DQ matching CLASS: <a href="URL" class="MyClass">Test 01</a>.
Single SQ matching CLASS: <a href="URL" class='MyClass'>Test 02</a>.
Single NQ matching CLASS: <a href="URL" class=MyClass>Test 03</a>.
Variable whitespace: <a href = "URL" class = MyClass >Test 04</a>.
Variable capitalization: <A HREF = "URL" CLASS = "MyClass" >Test 04</A>.
Reversed attribute order: <a class="MyClass" href="URL">Test 05</a>
Class before MyClass: <a href="URL" class="Pre MyClass">Test 06</a>.
Class after MyClass: <a href="URL" class="MyClass Post">Test 07</a>.
Sandwiched MyClass: <a href="URL" class="Pre MyClass Post">Test 08</a>.
Link with HTML content: <a class="MyClass" href="URL"><b>Test</b> 09</a>.
</p>

<h2>Paragraph contains links to be stripped (NO CLASS with "MyClass"):</h2>
<p>
Case does not match: TEST 10.
CLASS not whole word: TEST 11.
No class attribute: TEST 12.
Link with HTML content: <b>Test</b> 13.
</p>

希望提高他们的 regex-fu 的读者会很好地研究这个（相当长和复杂的）正则表达式。它为准确性和速度而精心手工制作，并实施了多种先进的效率技术。当然，它被充分注释以允许人类阅读。这个例子清楚地表明“正则表达式”已经演变成一种丰富的（非正则）编程语言。

请注意，总会有这种解决方案失败的边缘情况。例如，CDATA 部分、注释、脚本、样式和标签属性值中的邪恶字符串可能会导致此问题。（见上面的免责声明。）也就是说，这个解决方案在很多情况下都会做得很好（但永远不会100% 可靠！）

于 2012-06-27T03:42:55.763 回答
0

其他答案是明智的。但是，如果出于任何原因您坚持使用 REGEX 方法。尝试这个。

我假设您正在通过 PHP（或 .NET）执行 REGEX，因为您的模式包含一个否定的后视断言，JavaScript 不支持该断言。

我还将匹配与过滤出那些有坏类的匹配，因为 REGEX 不适合后者（因为类属性可能出现在链接的开始标记内的任何位置）。

$str = "<a href='bad_href' class='badClass'>bad link</a> <a href='good_href'>good link</a>";
preg_match_all('/<a.+(href ?= ?("|\')[^\2]*\2).*>.*<\/a>/U', $str, $matches);
foreach($matches[0] as $key => $match)
    if (preg_match('/class=(\'|")[^\1]*badClass[^\1]*\1/', $match))
        unset($matches[1][$key]);
$matches = $matches[1]; //array containing "href='good_href'"
于 2012-06-26T11:51:55.627 回答
0 
var aList= document.getElementsByTagName('a');
for (var i in aList) {
   if (aList.hasOwnProperty(i)) {
     if (aList[i].className.indexOf(YourClassName) != -1) continue;
    //... 
    //... Your code
   }
}
于 2012-06-26T12:23:16.393 回答