如何使用XPath计算XML中的元素?

时间:2014-03-13 17:33:43

标签: html xml xpath

我有一个基于w3schools课程的XML消息:

<?xml version="1.0" encoding="UTF-8""?>

<bookstore>

<book category="COOKING">
  <title lang="en">Everyday Italian</title>
  <author>Giada De Laurentiis</author>
  <year>2005</year>
  <price>30.00</price>
</book>

<book category="CHILDREN">
  <title lang="en">Harry Potter</title>
  <author>J K. Rowling</author>
  <year>2005</year>
  <price>29.99</price>
</book>

<book category="WEB">
  <title lang="en">XQuery Kick Start</title>
  <author>James McGovern</author>
  <author>Per Bothner</author>
  <author>Kurt Cagle</author>
  <author>James Linn</author>
  <author>Vaidyanathan Nagarajan</author>
  <year>2003</year>
  <price>49.99</price>
</book>

<book category="WEB">
  <title lang="en">Learning XML</title>
  <author>Erik T. Ray</author>
  <year>2003</year>
  <price>39.95</price>
</book>

</bookstore>

我有这个XPath脚本:

<!DOCTYPE html>
<html>
<body>
<script>

function loadXMLDoc(dname)
{
xhttp=new XMLHttpRequest();
xhttp.open("GET",dname,false);
xhttp.send("");
return xhttp;
}

var x=loadXMLDoc("books.xml");
var xml=x.responseXML;
path="/bookstore/book/price";

{
var nodes=xml.evaluate(path, xml, null, XPathResult.ANY_TYPE, null);
var result=nodes.iterateNext();

while (result)
  {
  document.write(result.childNodes[0].nodeValue);
  document.write("<br>");
  result=nodes.iterateNext();
  }
}

</script>
</body>
</html>

截至目前,代码正确显示了价格清单,这正是我想要的。但后来我想在最后显示找到的实例数量;在out case的情况下应该只返回4。 我尝试添加:

document.write("<br>");
document.write(count(//price));

,但它不起作用,我不知道哪里出错了。谢谢你的帮忙。

1 个答案:

答案 0 :(得分:0)

while (result)
{
  document.write(result.childNodes[0].nodeValue);
  document.write("<br>");
  result=nodes.iterateNext();
}
document.write(nodes.length);