Problem with charset and rewriting HTML content

Sorry about that ....... but pleae do not take my example litterly,what I was trygin to say that generally speking buffering cannot match long strings... the example I faced as far as I remember (I might be showing some mistakes) is rewriting this

var.                   Varname.     =                   "somevalue" 

And rewriting it to

var varname="somevalue"

But like I said before in complex irule like an irule that is use for identifying and encrypting uris treaming is not effecient.... so my issue is not specific to those example it is more general

Thank you hoolio