Iframe plugin uses deprecated attributes and allows invalid values in HTML5

[Tomasz Jakut]

Steps to reproduce

1. Open editor with iframe plugin (e.g. ​http://sdk.ckeditor.com/samples/fullpreset.html ) and clear its content.
2. Click "Iframe" button.
3. Set URL to http://wikipedia.org, "Width" to 100%, "Height" to 800px, "Align" to "Middle".
4. Check "Enable scrollbars" and "Show frame border".
5. Click OK.
6. Go into source mode and copy generated code into ​https://validator.w3.org/nu/#textarea
7. Validate HTML

Expected result

• Editor should not allow to set "Width" to "100%" (only digits should be allowed).
• Editor should not allow to set "Height" to "800px" (only digits should be allowed).
• No validation errors found.

Actual result

5 validation errors are found:

• Bad value 800px for attribute height on element iframe: Expected a digit but saw p instead.
• Bad value 100% for attribute width on element iframe: Expected a digit but saw % instead.
• The align attribute on the iframe element is obsolete.
• The frameborder attribute on the iframe element is obsolete.
• The scrolling attribute on the iframe element is obsolete.

[Jakub Ś]

#7207 was marked as duplicate.