Get DocType of an HTML as string with Javascript
Question
I know that I can access to doctype object via document.doctype or document.childNodes[0] but my problem is getting doctype as a string. I can do this in chrome and safari by calling document.doctype which returns <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> . However in Firefox, calling document.doctype returns DocumentType object.
Is there a way to get the doctype string in all browsers as in chrome and safari?
Thanks!
5 answers
solution1
77 ACCPTED 2012-04-15 13:14:57
In all compliant browsers (including Chrome/Safari), document.doctype also returns a DocumentType object. The following code can be used to generate a valid DOCTYPE string.
var node = document.doctype;
var html = "<!DOCTYPE "
+ node.name
+ (node.publicId ? ' PUBLIC "' + node.publicId + '"' : '')
+ (!node.publicId && node.systemId ? ' SYSTEM' : '')
+ (node.systemId ? ' "' + node.systemId + '"' : '')
+ '>';
This method returns the correct string for valid (HTML5) doctypes , eg:
-
<!DOCTYPE html> -
<!DOCTYPE html SYSTEM "about:legacy-compat"> -
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN" "http://www.w3.org/TR/REC-html40/strict.dtd">
Explanation of the code:
node.name # Holds the name of the root element, eg: HTML / html
node.publicId # If this property is present, then it's a public document type.
#>Prefix PUBLIC
!node.publicId && node.systemId
# If there's no publicId, but a systemId, prefix SYSTEM
node.systemId # Append this if present
solution2
53 2015-01-08 11:22:59
You can also use this one liner to get the current doctype. This will work in any modern browser and IE 9 and higher .
new XMLSerializer().serializeToString(document.doctype);
solution3
3 2012-05-02 07:36:12
function get_doctype()
{
var doctype =
'<!DOCTYPE ' +
document.doctype.name +
(document.doctype.publicId?' PUBLIC "' + document.doctype.publicId + '"':'') +
(document.doctype.systemId?' "' + document.doctype.systemId + '"':'') + '>';
return doctype;
}
solution4
1 2011-05-22 15:46:07
这就是你要找的吗？
alert(document.doctype.publicId);
solution5
1 2011-05-22 15:53:32
Concatenate DocumentType.name , .publicId and .systemId . Something like:
'<!DOCTYPE '+
DocumentType.name+' PUBLIC "'+ //maybe you should check for publicId first
DocumentType.publicId+'" "'+
DocumentType.systemId+'">'
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