None according to HTML 3.2. In HTML 4.0, the SCRIPT element is defined so that it has an obligatory TYPE attribute and some optional attributes. (In some drafts and implementations, the attribute LANGUAGE has been used, but it has been deprecated in favor of the TYPE attribute.)
Technically, these elements are defined with CDATA as the content type. As a result they may contain only SGML characters. All markup characters or delimiters are ignored and passed as data to the application, except for the character pair </ followed immediately by a letter (a - z, A - Z), This means that the end tag of the element (or of an element in which it is nested) is recognized. (Scripts may need to contain e.g. HTML end tags as data. Different scripting languages provide different methods for coping with this.)
The SCRIPT element was introduced into HTML 3.2 just a place holder for the introduction of support for scripting languages in future versions of HTML, such as HTML 4.0.