Is HTML case sensitive?
Case Sensitivity in HTML
HTML is not case sensitive when it comes to element names and attributes. For example, <H1>, <h1>, and <H1> will all be interpreted as the same heading element by the browser.
Example of Case Insensitivity
Important Notes
HTML tags and attributes are not case sensitive.
The convention is to write tags and attributes in lowercase for readability and consistency.
XHTML (a stricter version of HTML) is case sensitive, and requires lowercase tags and attributes.