DocumentType.before()
The DocumentType.before()
method inserts a set of
Node
or DOMString
objects in the children list of the
DocumentType
's parent, just before the DocumentType
.
DOMString
objects are inserted as equivalent Text
nodes.
Note: Putting nodes before the document's doctype will set the rendering mode to quirks mode in some browsers (Internet Explorer). It is not advisable to do this.
Syntax
before(... nodes)
Parameters
Exceptions
HierarchyRequestError
DOMException
-
Thrown when the node cannot be inserted at the specified point in the hierarchy.
Examples
Adding a conditional comment
Comment nodes are valid before doctype declarations but not advisable given they trigger quirks mode in IE. A conditional comment works for IE as well, though:
let docType = document.implementation.createDocumentType("html", "", "");
let myDoc = document.implementation.createDocument("", "", docType);
docType.before(document.createComment('<!--[if !IE]> conditional comment <![endif]-->'));
myDoc.childNodes;
// NodeList [<!--[if !IE]> conditional comment <![endif]-->, <!DOCTYPE html>]
Specifications
Specification |
---|
DOM Standard # ref-for-dom-childnode-before① |
Browser compatibility
BCD tables only load in the browser