Developer tools console Error# HTML1524 is incorrect - by IECustomizer

Status : 

  By Design<br /><br />
		The product team believes this item works according to its intended design.<br /><br />
		A more detailed explanation for the resolution of this particular item may have been provided in the comments section.

ID 806847 Comments
Status Closed Workarounds
Type Bug Repros 3
Opened 10/28/2013 10:49:21 PM
Access Restriction Public


Navigate to
and then display the developer tool console.... refresh the page to show suppressed console messages and errors.

the console of Developer tools shows:
HTML1524: Invalid HTML5 DOCTYPE. Consider using the interoperable form "<!DOCTYPE html>".
File: iframe-contentdocument.aspx, Line: 1, Column: 1

while the documentation at


"Invalid DOCTYPE. The shortest valid doctype is "<!DOCTYPE html>"."

Both are incorrect in this case as the DTD is valid

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Posted by Microsoft on 2/26/2016 at 8:28 AM
Sorry for the delay in response.

This doesn't match the permitted "obsolete" HTML 4.01 doctypes as described below and will be closed out as By Design. Also note that we are not working on IE feature bugs going forward unless they are security related. We do appreciate the time spent filing the feedback for us.

All the best,
The MS Edge Team
Posted by Vismaya Software on 10/28/2015 at 9:16 PM
Even after 3 years still this issue exists in Windows 7 and IE also. It happens even when page already has valid doctype. Why Microsoft is ignoring this issue? Atleast close this saying cannot be fixed or giving reasons.
Posted by ihopethisdisplaynameisnotinuse on 3/7/2014 at 8:29 PM
Reproduced on IE11/Vista. Removing the linebreak from the <!DOCTYPE> prevented a similar error appearing on my site.
Posted by Microsoft on 11/7/2013 at 12:26 PM
Thank you for your feedback. We will be investigating this issue further.
We'll keep you informed of the progress of this bug.
Best regards,

The Internet Explorer Team