Beware of English use!
I was working on a little project, and used hebrevc to reverse Hebrew in a loop. The hebrevc function got a variable as an argument. Sometimes the variable was pure English and sometimes it was hebrew.
Suddenly I found out that the English too was cut with BR tags, which made it look funny - the last line was the first.
If you're going to use that function in mixed text, don't forget to check the language before using the function.