如何获取MSXML对DOM的支持程度

可以使用Document Object Model (Core) Level 1中Implementation的hasFeature方法获取相应信息。由于DOM Core Level 1是最基本的DOM实现，只要基本支持DOM的实现，无论MSXML、MSHTML或者Chrome还是Firefox，都应该可以使用这个函数。下面是一段简单的实现：

var xmlDoc = new ActiveXObject("Msxml2.DOMDocument.3.0");
xmlDoc.async = false;
xmlDoc.loadXML("<foo/>");
if (xmlDoc.parseError.errorCode != 0) {
var myErr = xmlDoc.parseError;
WScript.Echo("You have error " + myErr.reason);
} else {
var features = ["XML", "DOM", "MS-DOM", "XSLT", "SCHEMA"];
var versions = ["0.5", "1.0", "2.0"];
var impl;
impl = xmlDoc.implementation;
for (var i = 0; i < features.length; i++) {
for (var j = 0; j < versions.length; j++) {
if (impl.hasFeature(features[i], versions[j]) == 0)
WScript.Echo(features[i] + " " + versions[j] + ": not supported");
else
WScript.Echo(features[i] + " " + versions[j] + ": supported");
}
}
}

有趣的是，MSXML3对Schema的支持居然是0.5，想必是仅仅支持XDR而不是XML Schema的原因吧！