The jQuery.isXMLDoc() utility returns true when a DOM node belongs to an XML document — or is the XML document itself. This tutorial covers syntax, official HTML vs XML examples, pairing with $.parseXML(), plugin guard patterns, and how jQuery uses the check internally.
$.isXMLDoc(node)
true / false
false
true
Common source
Branch logic
Web pages you build every day live in an HTML document. But JavaScript also works with XML documents — AJAX responses, RSS/Atom feeds, configuration files, and strings parsed with jQuery.parseXML(). HTML and XML nodes are both DOM objects, yet they follow different rules for namespaces, tag names, and attributes.
jQuery provides jQuery.isXMLDoc() (also written $.isXMLDoc()) to answer: “Is this node part of an XML document?” jQuery’s selector engine and DOM helpers use that answer internally. Plugin authors use it to avoid treating XML nodes like ordinary HTML elements.
jQuery.isXMLDoc() MethodjQuery.isXMLDoc(node) returns true when node is an XML document (nodeType 9) or any element, text, or attribute node whose owning document has a non-HTML root element.
On a typical web page, both document and document.body return false because the root element is <html>. Parsed XML from $.parseXML() returns true for the document and its elements.
Think HTML page = false. Parsed XML string = true. The method checks the document root — not the node’s tag name alone.
General form of jQuery.isXMLDoc:
jQuery.isXMLDoc( node )
// or
$.isXMLDoc( node )true if node is or belongs to an XML document.false for HTML document nodes and non-node values (in jQuery 3.7+).function handleNode(node) {
if ($.isXMLDoc(node)) {
return processXmlNode(node);
}
return processHtmlNode(node);
}| Node | $.isXMLDoc() |
|---|---|
document (HTML page) | false |
document.body | false |
$.parseXML("<root/>") | true |
XML documentElement | true |
| Child of parsed XML | true |
null / undefined | false (jQuery 3.7+) |
Plain object {} | false |
$.isXMLDoc vs $.type vs $.isPlainObjectThree different questions — XML context, generic type, and plain object shape.
XML doc?DOM in XML context
"object"HTML & XML nodes
{} mapsNot for DOM nodes
create XMLPair with isXMLDoc
Each example uses $.isXMLDoc() with jQuery 3.7.1. Open DevTools or use the Try-it links to run them interactively.
Official jQuery API examples — HTML document nodes return false.
document and body Return falseThe canonical cases from the jQuery documentation for a normal web page.
console.log($.isXMLDoc(document)); // false
console.log($.isXMLDoc(document.body)); // falseYour tutorial page uses an HTML document whose root is <html>. jQuery detects that root name and returns false — these nodes are not in an XML document.
Parsed XML, element checks, guards, and traversal.
trueUse $.parseXML() to create an in-memory XML document, then test it.
var xmlDoc = $.parseXML("parseXML builds a real XML document object. Its root is <catalog>, not <html>, so isXMLDoc returns true.
Any node within an XML document — not just the document node — returns true.
var xmlDoc = $.parseXML("isXMLDoc walks to the owning document’s root element. If that root is not HTML, every node in that tree is treated as XML — including nested elements like <book>.
Branch attribute reading — XML preserves case; HTML is often case-insensitive.
function readTitle(node) {
if (!node || !node.getAttribute) {
return null;
}
if ($.isXMLDoc(node)) {
return node.getAttribute("title");
}
return node.getAttribute("title") || node.getAttribute("TITLE");
}
var xmlDoc = $.parseXML("Plugins that accept “any DOM node” must not assume HTML-only behavior. isXMLDoc is the first branch before case folding, .innerHTML, or other HTML-specific APIs.
Wrap XML nodes in a jQuery collection only after confirming XML context.
var xmlDoc = $.parseXML(
"jQuery can query XML nodes when you pass the XML root or elements as context. Confirming XML first prevents accidentally mixing HTML document queries with detached XML trees.
jQuery.isXMLDoc() Inspects the Document RootUse node.ownerDocument or treat node as the document if it is one.
Get the root element — <html> for web pages, custom tags for XML.
If the root is not an HTML document element, the node is XML.
true for XML trees; false for normal HTML pages.
isWindow).$.parseXML() when building XML documents from strings.document on a web page always returns false.$.parseXML(), $.type(), $.isPlainObject().jQuery.isXMLDoc() has been part of jQuery since jQuery 1.1.4+. It works wherever jQuery and DOM Level 2 documents are available — all modern browsers and legacy IE when paired with a supported jQuery build.
Supported in jQuery 1.x, 2.x, and 3.x. Still present in current 3.7 releases — use with $.parseXML() for string-to-XML workflows.
Bottom line: Safe in any project that already includes jQuery. Validate nodes before calling — jQuery 3.7+ returns false for falsy input instead of throwing.
The jQuery.isXMLDoc() utility tells you whether a DOM node lives in an XML document. On normal HTML pages, document and document.body return false; parsed XML from $.parseXML() returns true for the document and its elements.
Use it when plugins or utilities must branch between HTML and XML DOM rules — before assuming case-insensitive tags, innerHTML, or other HTML-only behavior.
$.isXMLDoc$.parseXML() to create testable XML documentsisXMLDoc is truedocument and parsed XML in unit demostypeof node === "object" means XMLisPlainObject on DOM nodesinnerHTML to XML nodes blindlydocument always returns falsejQuery.isXMLDoc()Detect XML DOM contexts the jQuery way.
XML context
APIfalse
Pagetrue
XMLInherit
TreeBranch
PatternjQuery’s selector engine uses XML detection internally because XML documents follow different matching rules than HTML — tag names are case-sensitive and namespaces matter. That is why a tiny utility like isXMLDoc has existed since jQuery 1.1.4, long before most tutorials even mention parseXML.
Test whether a DOM element is a descendant of another.
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