Question

以下HTML显示第3次搜索（搜索“练习指南专业版”）不起作用，因为文本“练习指南”放在<strong></strong>标记之间...是否可以实现XPath搜索到绕过文本之间的HTML标签？

<html>
<head>
<meta http-equiv="X-UA-Compatible" content="chrome=1">
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<meta name="apple-mobile-web-app-capable" content="yes">
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
<title>Xpath Test</title>

<script type="text/javascript">
var search = function (button) {
    var searchTxt = button.value;
    var xpath = '//*[contains(translate(text(),\'ABCDEFGHIJKLMNOPQRSTUVWXYZ\', \'abcdefghijklmnopqrstuvwxyz\'), \'' + searchTxt.toLowerCase() + '\')]';
    var nodes = null;

    if (document.evaluate) { 
        nodes = document.evaluate(
          xpath,
          document,
          null,
          XPathResult.ORDERED_NODE_ITERATOR_TYPE,
          null
        );

        var node = nodes.iterateNext ();
        if (node) {
            while (node) {
                var nodeXpath = createXPathFromElement(node);
                alert("Found!!!\n xpath: " + nodeXpath);
                node = nodes.iterateNext ();
            }
        } else {
            alert("No results found.");
        }
    } else {  
        alert("Your browser does not support the evaluate method!");
    }
  }

  function createXPathFromElement(elm) {
    var allNodes = document.getElementsByTagName('*'); 
    for (segs = []; elm && elm.nodeType == 1; elm = elm.parentNode) 
    {  
        for (i = 1, sib = elm.previousSibling; sib; sib = sib.previousSibling) { 
            if (sib.localName == elm.localName)  i++; 
        };
        segs.unshift(elm.localName.toLowerCase() + '[' + i + ']'); 
    }; 
    return segs.length ? '//' + segs.join('//') : null; 
  }
</script>
</head>

<body>
<table>
    <tr>
        <td>
            <p>&#160;</p><h3><strong><span class="color-1">PRINCIPLES OF PATIENT CARE</span></strong></h3><p class="noindent"><strong><span class="color-1">Evidence-Based Medicine</span></strong> Evidence-based medicine refers to the concept that clinical decisions are formally supported by data, preferably data that are derived from prospectively designed, randomized, controlled clinical trials. This is in sharp contrast to anecdotal experience, which may often be biased. Unless they are attuned to the importance of using larger, more objective studies for making decisions, even the most experienced physicians can be influenced by recent encounters with selected patients. Evidence-based medicine has become an increasingly important part of the routine practice of medicine and has led to the publication of a number of practice guidelines.</p>
            <p>&#160;</p><p class="noindent"><strong><span class="color-1">Practice Guidelines</span></strong> Professional organizations and government agencies are developing formal clinical-practice guidelines to aid physicians and other caregivers in making diagnostic and therapeutic decisions that are evidence-based, cost-effective, and most appropriate to a particular patient and clinical situation. As the evidence base of medicine increases, guidelines can provide a useful framework for managing patients with particular diagnoses or symptoms. They can protect patients—particularly those with inadequate health care benefits—from receiving substandard care. Guidelines can also protect conscientious caregivers from inappropriate charges of malpractice and society from the excessive costs associated with the overuse of medical resources. There are, however, caveats associated with clinical practice guidelines since they tend to oversimplify the complexities of medicine. Furthermore, groups with differing perspectives may develop divergent recommendations regarding issues as basic as the need for periodic sigmoidoscopy in middle-aged persons. Finally, guidelines do not—and cannot be expected to—account for the uniqueness of each individual and his or her illness. The physician’s challenge is to integrate into clinical practice the useful recommendations offered by experts without accepting them blindly or being inappropriately constrained by them.</p>               
        </td>
    </tr>
    <tr>
        <td>
            Search for <input type="button" onclick="search(this)" value="Practice Guidelines" /> Success.
        </td>
    </tr>
    <tr>
        <td>
            Search for <input type="button" onclick="search(this)" value="Professional" /> Success.
        </td>
    </tr>
    <tr>
        <td>
            Search for <input type="button" onclick="search(this)" value="Practice Guidelines Professional" /> No result since text 'Practice Guidelines' is inside &lt;strong&gt;&lt;strong/&gt;, and  'Professional' is out side.     
        </td>
    </tr>
</table>
</body>
</html>

Answer 1

是。您可以使用normalize-space()。 （为了便于阅读而换行）

var xpath = "
  //*[
    contains(
      translate(
        normalize-space(.), 
        'ABCDEFGHIJKLMNOPQRSTUVWXYZ', 
        'abcdefghijklmnopqrstuvwxyz'
      ), 
      normalize-space('" + searchTxt.toLowerCase() + "')
    )
  ]
";

请注意，这将找到包含相应文本的节点的整个层次结构，包括<html>元素。我想你会对“最深层嵌套”的节点感兴趣。

另请注意，您可能希望从searchTxt中删除单引号，因为它们会破坏XPath表达式。

Answer 2

可能还有一个递归方法，它查看根元素的textContent / innerHTML以查看是否找到匹配项。如果是这样，请关闭匹配的firstChild节点，依此类推，直到匹配失败，此时才会找到包含文本的元素。

也适用于与文本的多个匹配。

XPath可能会更快，但可能不会得到更好的支持（尽管它似乎适用于所有现代浏览器）。

XPath搜索HTML标记

2 个答案: