Firefox & Javascript

Does anyone around here know how Firefox processes javascript? Does FF parse and execute js before writing it to disk, or does it write it to disk before execution?

The answer relates to whether a web or http AV scanner would provide any benefit by scanning the javascript prior to it being written to disk where the on access scanner would get a shot at it.

Would anyone know this behavior for Internet Explorer, which I believe uses script interpreters built into Windows.

 

scripts are generally part of the page itself (not separate) and from observation the browser does not wait until it has received the entire contents of the page before it starts rendering it... i don't know for sure, but the safe money is on the execution of scripts and the writing of scripts to disk being independent of one another (which means there probably is some benefit to using a web scanner)...