The detected DOCTYPE Declaration "" has been suppressed and the DOCTYPE for "HTML 4.01 Transitional" inserted instead, but even if no errors are shown below the document will not be Valid until you update it to reflect this new DOCTYPE. The document located at was tentatively found to be Valid. That means it would validate as HTML 4.01 Transitional if you updated the source document to match the options used (typically this message indicates that you used either the Document Type override or the Character Encoding override). Source Listing Below is the source input I used for this validation: 1: 2: 3: 4: etc.