getElementsByClassName()和querySelectorAll()在处理AJAX响应时是否有什么需要注意的吗?
在Firefox 9、Chrome 17和可能所有浏览器中,当对AJAX响应执行这两个函数时,似乎都会返回一个空数组。可以参考以下链接进行查看。
我可以调用document.getElementsByClassName('findme')或anyElement.getElementsByClassName('findme')来查找当前页面DOM中的任何元素,但由于某种原因,在处理AJAX请求返回的XML文档时似乎不起作用。请注意,getElementsByTagName可用于AJAX,在Firebug中也可以看到这些元素具有“findme”类。
var inMem = document.createElement('div');
var findme1 = document.createElement('div');
var findme2 = document.createElement('div');
findme1.className = 'findme';
findme2.className = 'findme';
inMem.appendChild( findme1 );
inMem.appendChild( findme2 );
$('#inMem').html( 'found ' + inMem.getElementsByTagName('div').length +
' divs in the detached div<br/>' +
'found ' + inMem.getElementsByClassName('findme').length +
' findme elements by ClassName<br/>' +
'found ' + inMem.querySelectorAll('.findme').length +
' findme elements using querySelectorAll()');
var inDoc = document.getElementById('inDoc');
inDoc.innerHTML = 'found ' + inDoc.getElementsByTagName('div').length +
' divs in the doc<br/>' +
'found ' + inDoc.getElementsByClassName('findme').length +
' findme elements by ClassName<br/>' +
'found ' + inDoc.querySelectorAll('.findme').length +
' findme elements using querySelectorAll()';
$.post( '/echo/xml/',
{xml:'<div id="wrapper"><div class="findme" id="findme1">findme 1</div><div class="findme">findme 2</div></div>'},
function(data, textStatus, jqXHR) {
data = jqXHR.responseXML.documentElement;
var msg = 'found ' + data.getElementsByTagName('div').length +
' divs in the AJAX response, <br/>' +
'found ' + data.getElementsByClassName('findme').length +
' findme elements by ClassName<br/>' +
'found ' + data.querySelectorAll('.findme').length +
' findme elements using querySelectorAll()<br/>' +
'The class name of the first div: ' + data.firstElementChild.className +
' (className) or ' + data.firstElementChild.attributes['class'].value + ' (attributes["class"].value)';
$('#ajax').html(msg);
}
);
<h2>In-Memory</h2>
<div id="inMem"></div>
<h2>In HTML Document</h2>
<div id="inDoc">
<div class="findme"></div>
<div class="findme"></div>
</div>
<h2>AJAX XML Response</h2>
<div id="ajax">wait...</div>