The <strong> Element
As defined in the HTML Living Standard, the <strong> element represents strong importance, seriousness, or urgency for its contents.
<p>This is <strong>extremely</strong> important.</p>
View HTML Living Standard: The strong element
Importance vs. Emphasis
HTML distinguishes between different types of text "strength." Choosing the correct one is vital for programmatic accuracy:
<strong>: Serious importance or urgency. The meaning of the text is globally important.<em>: Emphatic stress. It changes how a specific sentence is read or understood (e.g., "I did audit the site").<b>: Utilitarian attention-drawing. Used for keywords or product names where no extra importance is implied.
WCAG Requirement: Info and Relationships
Success Criterion 1.3.1 (Level A): Information, structure, and relationships conveyed through presentation can be programmatically determined.
When a screen reader encounters a <strong> tag, users can often hear a change in tone or an announcement of "strong" (depending on their settings). This ensures that the seriousness of the content is perceivable to users who cannot see the bold formatting.
Nesting Strong Importance
The <strong> element can be nested. Each level of nesting represents a higher level of importance or urgency.
<p>
<strong>Danger: <strong>High Voltage</strong> - Do not touch.</strong>
</p>
A11y Tip: Use with Caution
Do not wrap entire paragraphs in <strong>. If a whole section is important, use a heading or a semantic container with a border. <strong> is best used for specific words or phrases that require immediate attention. Overuse can dilute the impact and overwhelm screen reader users.