Dynamically change mweb-default-major-mode

[cuppa-t-lager]

Hi... is there a way to dynamically change the mweb-default-major-mode... once a file has been opened. I've started a new role developing coldfusion. Here files can be written using either based or script(){} based code. I find I open up a script based file with html-mode set as the mweb-default-major-mode and can't easily quickly switch the file to JavaScript-mode. Any ideas appreciated. Thanks