Ecmascript 3 denotes 'char' as "future reserved word"

Yuicompressor fails to compress this file because 'char' is a "future reserved word". The fix contains equivalent functionality avoiding the bare 'char' word.

Ecmascript 5 dropped this reserved word, but supporting Ecmascript 3 is just a one line change.

See Ecmascript 3 spec, section 7.5.3: http://www.ecma-international.org/publications/files/ECMA-ST-ARCH/ECMA-262,%203rd%20edition,%20December%201999.pdf