Thanks Aaron, what a pitty that there is a different between the behavior of keyup and keydown. I thought to write a letter is the same process (divided into keydown, keypress and keyup) I think for counting letters the best way is to use the keyup method. Any idea how to realize a letter counting with the possibility<http://dict.leo.org/ende?lp=ende&p=DOKJAA&search=possibility>to stop the writing event?
Here my complete class with different events to demonstrate the behavior. http://jsfiddle.net/H7GCy/3/
