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The old <acronym> element in previous versions is now obsolete, in HTML5 you must use <abbr> instead.
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The page scanned is using an obsolete doctype, instead of the expected <!DOCTYPE html>.
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>A <script> element has been found that is using the now obsolete charset attribute. You can safely remove this attribute.
For example, this is using both type and charset attributes, with their default values. Both can be removed:
<script src="app.js" type="text/javascript" charset="UTF-8"></script>and just use this:
<script src="app.js"></script>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 element, used to define the font face, size and color in previous versions of HTML, is no longer valid in HTML5.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 <script> tag allows authors to include dynamic scripts and data blocks in their documents. This tag accepts two optional attributes, type (which is unnecessary if it’s JavaScript, as that’s the default), and src to indicate the URL of the external script to use.
The language attribute is now obsolete and should not be used.
The <option> element no longer accepts a name attribute, which is now obsolete.
Example:
<select id="pet-select">
<option value="">--Please choose an option--</option>
<option value="dog">Dog</option>
<option value="cat">Cat</option>
<option value="hamster">Hamster</option>
</select>The <meta> element no longer accepts a scheme attribute, it’s now obsolete and should be removed.
For example, old documents adhering to old definitions in DCMI (Dublin Core Metadata Initiative) use this HTML tag to define a date:
<meta name="DC.Date.Created" scheme="W3CDTF" content="2009-11-30" />As the scheme attribute is now obsolete, it should now be removed. The following HTML code will pass current validations, but you should check the exact definition to use if you want to keep using the DCMI tags.
<meta name="DC.Date.Created" content="2009-11-30" />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>In HTML5, there’s no need to specify the version attribute - it is now obsolete. Here’s an example minimal HTML document to start with:
<!DOCTYPE html>
<html lang="en">
<head>
<title>Test</title>
</head>
<body>
<p></p>
</body>
</html>