HTML Guide

Non-space characters found without seeing a doctype first. Expected “<!DOCTYPE html>”.

A missing or incorrectly placed <!DOCTYPE html> declaration at the very start of your HTML document causes this error.

The <!DOCTYPE html> declaration must be the very first thing in your HTML file, before any HTML code. This declaration tells the browser to use standards mode, ensuring reliable rendering. Without it, browsers may behave unpredictably or trigger quirks mode, and validators will issue an error.

Correct Example:

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Valid HTML Document</title>
  </head>
  <body>
    <p>Hello, world!</p>
  </body>
</html>

Incorrect Example (doctype missing):

<html lang="en">
  <head>
    <title>Invalid HTML Document</title>
  </head>
  <body>
    <p>Hello, world!</p>
  </body>
</html>

Incorrect Example (doctype not at the very start):

Some misplaced text.

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Invalid Placement</title>
  </head>
  <body>
    <p>Hello, world!</p>
  </body>
</html>

Always ensure <!DOCTYPE html> is the first line.

Learn more:

Related W3C validator issues

Almost standards mode doctype. Expected “<!DOCTYPE html>”.

End of file seen without seeing a doctype first. Expected “<!DOCTYPE html>”.

HTML documents are expected to start with a first line containing the Document Type Declaration, that defines the HTML version used. Since HTML5, it’s just <!DOCTYPE html>, which must appear before the start <html> tag.

Here’s an example of a minimal HTML5 document:

<!DOCTYPE html>
<html>
  <head>
    <title>Test</title>
  </head>
  <body>
    <p></p>
  </body>
</html>

Misplaced non-space characters inside a table.

The W3C HTML Validator issue “Misplaced non-space characters inside a table” usually occurs when there are text nodes (or other elements) that are not properly placed within table elements. In HTML, all text content should be contained within table cells.

How to Fix the Issue

To resolve this issue, ensure that all text content is placed inside <td> or <th> elements, which are the valid child elements of <table>, <tr>, and related elements. Here’s how you can identify and fix the issue:

Example of Incorrect Table Structure

<table>
  <tr>
<!-- This is misplaced content -->

    <td>First Cell</td>
    <td>Second Cell</td>
  </tr>
</table>

Corrected Table Structure

<table>
  <tr>
<!-- All text should be inside <td> or <th> -->

    <td>First Cell</td>
    <td>Second Cell</td>
  </tr>
</table>

Guidelines

Text Content: Ensure that all text (including any headers or titles) is wrapped in <td> (for data cells) or <th> (for header cells). Keep in mind that event the non-breaking space character ( ) counts as text.
Table Structure: Remember a typical structure for a table includes <table> containing one or more <tr> elements, which in turn contain the <td> or <th> elements.
No Direct Text Nodes: Avoid having any direct text nodes outside of the cell elements within the table.

Obsolete doctype. Expected “<!DOCTYPE html>”.

Quirky doctype. Expected “<!DOCTYPE html>”.

doctype
html

The <!DOCTYPE html public "-//W3C//DTD HTML 4.0 Transitional//EN"> doctype triggers quirks mode in modern browsers and is not compliant with HTML5 standards.

The HTML5 specification requires the use of a simple doctype declaration, which ensures standards mode rendering. The correct doctype is <!DOCTYPE html>, which must appear at the very top of every HTML5 document. Legacy doctypes like HTML 4.0 Transitional are obsolete for modern web development and can cause inconsistent browser behavior.

Example of correct usage:

<!DOCTYPE html>
<html lang="en">
  <head>
    <title>Valid HTML5 Doctype Example</title>
  </head>
  <body>
    <p>Your content here.</p>
  </body>
</html>

Replace any legacy or malformed doctype with the above declaration to conform to current HTML standards.

Start tag seen without seeing a doctype first. Expected “<!DOCTYPE html>”.

Here’s an example of a minimal HTML5 document:

<!DOCTYPE html>
<html>
  <head>
    <title>Test</title>
  </head>
  <body>
    <p></p>
  </body>
</html>

Stray doctype.

All HTML documents must start with a <!DOCTYPE> (Document Type Declaration), that informs browsers about the type and version of HTML used to build the document. In HTML5, this is simply <!DOCTYPE html> and must appear at the start of the document.

Here is an example of a minimal HTML document, including the Document Type Declaration at its start:

<!DOCTYPE html>
<html>
  <head>
    <title>Test</title>
  </head>
  <body>
    <p></p>
  </body>
</html>