使用JavaScript和XPath从DOM中选择元素 [英] Selecting element from DOM with JavaScript and XPath
本文介绍了使用JavaScript和XPath从DOM中选择元素的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图找出如何使用xpath和JavaScript（这是这里唯一的选择）在下面的代码中选择textarea。
I'm trying to figure out how to select the textarea in the code below using xpath and JavaScript (which is the only option here).
<body>
<div id="calculator">
<div id="calculatorController">
<form action="#" method="get" onsubmit="return false">
<p>
<textarea disabled="disabled"></textarea>
</p>
</form>
...
我试图做这样的事情
var element = document.evaluate( '//body/form/p/textarea' ,document, null, XPathResult.ANY_TYPE, null );
// and write back
element.value = "Hello textarea";
但是失败
任何人都渴望帮助？
谢谢
此下方更新
======================================== ==================
============================================================
整个代码块看起来像这样。
不要忘记 window.onload = function（）
The entire block of code looks like this.
Don't forget the window.onload=function()
<html>
<head>
<script type='text/javascript'>
//<![CDATA[
window.onload=function(){
var element = document.evaluate( '//body//form/p/textarea' ,document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null ).singleNodeValue;
if (element != null) {
element.value = 'Hello textarea';
}
}
//]]>
</script>
</head>
<body>
<div id="calculator">
<div id="calculatorController">
<form action="#" method="get" onsubmit="return false">
<p>
<textarea disabled="disabled"></textarea>
</p>
</form>
</div>
</div>
</body>
</html>
推荐答案
评估方法不返回DOM节点似乎期待。您需要
The evaluate method does not return a DOM node as you seem to expect. You would need
var element = document.evaluate( '//body//form/p/textarea' ,document, null, XPathResult.FIRST_ORDERED_NODE_TYPE, null ).singleNodeValue;
if (element != null) {
element.value = '...';
}
这篇关于使用JavaScript和XPath从DOM中选择元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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