Home/ Questions/Q 7787475
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-01T20:41:04+00:00

I know that I can access to doctype object via document.doctype or document.childNodes[0] but

  • 0

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!

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    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
    • 0