HTML Checking for Large Sites
Rocket Validator integrates the W3C Validator HTML checker into an automated web crawler.
The <tt> tag, used in HTML4 to apply a monospaced (fixed width) font to the text, was deprecated in HTML5. Instead, you should use CSS to apply the desired font.
Example, instead of this deprecated code:
<tt>This is deprecated</tt>
You can define a monospaced text using font-family:
<span style="font-family: monospace;">This is monospaced text</span>Learn more:
Related W3C validator issues
The <big> tag is now obsolete. It was used to increase the size of text, you can do that using CSS instead. For example:
<p>Now this is <span style="font-size: larger;">big</span></p>The <font> element, used to define the font face, size and color in previous versions of HTML, is no longer valid in HTML5. Instead, you should rely on CSS styles.
For example, you can define a font size of 12px, bold text with inline styles like this:
<p style="font-size: 12px; font-weight: bold;">some text</p>The <table> element does not accept a height attribute. Use CSS instead.
To query for the size of the viewport (or the page box on page media), the width, height and aspect-ratio media features should be used, rather than device-width, device-height and device-aspect-ratio, which refer to the physical size of the device regardless of how much space is available for the document being laid out. The device-* media features are also sometimes used as a proxy to detect mobile devices. Instead, authors should use media features that better represent the aspect of the device that they are attempting to style against.
The width media feature describes the width of the targeted display area of the output device. For continuous media, this is the width of the viewport including the size of a rendered scroll bar (if any).
In the following example, this media query expresses that the style sheet is only linked if the width of the viewport 768px maximum:
<link rel="stylesheet" media="only screen and (max-width: 768px)" href="styles.css">Still checking your large sites one page at a time?
Save time using our automated web checker. Let our crawler check your web pages on the W3C Validator.
To query for the size of the viewport (or the page box on page media), the width, height and aspect-ratio media features should be used, rather than device-width, device-height and device-aspect-ratio, which refer to the physical size of the device regardless of how much space is available for the document being laid out. The device-* media features are also sometimes used as a proxy to detect mobile devices. Instead, authors should use media features that better represent the aspect of the device that they are attempting to style against.
The width media feature describes the width of the targeted display area of the output device. For continuous media, this is the width of the viewport including the size of a rendered scroll bar (if any).
In the following example, this media query expresses that the style sheet is only linked if the width of the viewport is greater than 768px:
<link rel="stylesheet" media="only screen and (min-width: 768px)" href="styles.css">A CSS definition for background-image could not be understood by the parser. Check its definition to ensure that it’s well formed and that it contains an appropriate value.
Still checking your large sites one page at a time?
Save time using our automated web checker. Let our crawler check your web pages on the W3C Validator.
The value on the display property is not valid.
The display CSS property sets whether an element is treated as a block or inline element and the layout used for its children, such as flow layout, grid or flex.
The specified CSS filter is not a standard one, and may only work in some browsers.
font-display isn’t a CSS property, it’s a descriptor for use with the @font-face at-rule.
The value passed to the font-size property is invalid, probably missing the amount of px.
The font-size CSS property sets the size of the font, and this size can be expressed in different units, like em, % or px.
Example:
<!DOCTYPE html>
<html>
<head>
<title>Font-size Example</title>
<style>
p {
font-size: 16px;
}
</style>
</head>
<body>
<p>This is an example of a paragraph with a font-size of 16px.</p>
</body>
</html>Still checking your large sites one page at a time?
Save time using our automated web checker. Let our crawler check your web pages on the W3C Validator.