Using a negative look multiple times (or matching multiple characters with ^)?

I want to do something like this:

/<script[^>]*>(?!<\/script>)*<\/script>/g

to combine all script tags in an html string using javascript.

I know this will not work, but I cannot find any other solutions. script -tag can either use the src attribute, or close it immediately after ( <script src="..." type="text/javascript"></script>), or it can contain code in script -tag ( <script type="text/javascript">...</script>)