typeAttribute

The type attribute is an HTML attribute used to declare the media type or data type of a resource associated with an element. It informs a user agent how to interpret or process the linked, embedded, or controlling resource. The attribute typically holds a MIME type or a value that indicates the kind of control an element should provide.

In HTML, the type attribute appears on several elements. Common examples include script, style, and link, where it specifies the MIME type of the resource (for example, text/javascript for a script or text/css for a stylesheet). The type attribute also appears on form controls such as input and button to indicate the kind of control (for inputs, values like text, checkbox, radio; for button, values like submit or reset). Additional elements that may use type include object, embed, source, and track, where it identifies the nature of the embedded or linked resource.

HTML5 has reduced the necessity of the type attribute in many cases, since the browser can infer the intended type from context. For example, script elements default to JavaScript, and stylesheets are recognized by their link or style context. However, the type attribute remains important for specifying non-default content types, module scripts (type="module"), or when precise MIME typing is required for interoperability or validation.

Best practices include ensuring the value matches the resource’s actual MIME type as served by the server, and avoiding reliance on type for security alone. Mismatched types can affect loading behavior and, in some cases, trigger MIME sniffing protections. In XHTML documents, the type attribute is required for some elements, whereas in HTML5 it is optional in many cases.