LiveUploadAccept

Creates a policy containing one or more file extensions or media types.

Leading and trailing whitespace is removed from every filter. Extensions start with ., while media filters contain one non-edge / and may use a wildcard subtype, for example any image type. This is deliberately shallow syntax validation rather than complete MIME parsing. Preflight lowercases filters and browser-reported values before matching.

Validates and creates an accept policy without throwing.

The input must contain at least one filter. Filters are trimmed, must remain non-empty and unique by case-sensitive equality, and must be either an extension beginning with . or a media-like value containing exactly one non-leading, non-trailing /. No complete MIME syntax validation is performed.