Most Likely Cause and Fix
Your HTML5 markup contains a
<iframe> element with
align attribute in the form:
<iframe align="foo" … />
This attribute is no longer present in HTML5. You should use CSS to achieve the same effect:
<iframe style="<use-relevant-CSS-rule>" … />
What This Error Means
There are three aspects to a web-based document:
Structure: the underlying arrangement of the document and the elements contained within; handled by HTML
Presentation: how elements look and where on the page they're placed; handled by CSS.
The appearance of and placement text and other page elements is a presentational matter and as such is best implemented at the presentational layer and handled by CSS.
HTML5 follows this approach and removes various presentational attributes previously specified on elements in markup in preference of CSS rules that can achieve the equivalent effect.
This error is letting you know that you have presentational markup in your HTML that is no longer valid and that you should instead remove such attributes and apply relevant CSS rules.
How To Fix It
For text alignment within elements
Use the CSS
in preference of outdated presentational markup:
There is no general solution as the changes you need to make are dependent on the elements on which you used obsolete presentational attributes, the attributes that were used and the expected outcome.
Ensure all presentational aspects of your document are handled not in markup but in CSS.