Yes, there is - there was a version 1.2 of JavaScript which one sees
used from time to time as the value of the (deprecated) language
attribute. Using it there can have serious ramifications depending on
the browser. Using it as the value of the type attribute has possibly
more serious ramifications because it will stop the script content from
being executed at all in some browsers but not others.
Whether one effect is more serious than the other is moot.
The HTML 4 Strict DTD does not define any values for a script element's
type attribute, nor the case of tags or attribute names. HTML 4 is
case insensitive:
<URL:
http://www.w3.org/TR/html4/intro/sgmltut.html >
The case sensitivity of attribute values is defined in the HTML
specification, not the DTD.
<URL:
http://www.w3.org/TR/html4/interact/scripts.html#edef-SCRIPT >