Great optimization @fflorent.  Ran a quick test on a page with 43 scripts in the file filter (note: my box has an Intel i3570 overclocked CPU so the performance is a bit faster than typical).  Here are the results:

"aaa/aaa/aaa/aaa/aaa/aaa/aaa/aaa/aaa/aaa"
	escape() - 15ms
	indexOf() - 6ms

"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
	escape() - 8ms
	indexOf() - 1ms
	
"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
	escape() - 14ms
	indexOf() - 2ms

Typically I thought a compiled regex would outperform indexOf() with longer or more complex strings, but you proved me wrong =)