Added 'var' to example to be strict mode compliant
Added 'var' to example to be strict mode compliant

closes #206

[ci skip]

SheetJS/js-xlsx,iCasa/js-xlsx,iCasa/js-xlsx,thien-thach/searchFromExcel,SheetJS/js-xlsx,kaktus40/js-xlsx,kaktus40/js-xlsx,SheetJS/js-xlsx,thien-thach/searchFromExcel,iCasa/js-xlsx,SheetJS/js-xlsx,kaktus40/js-xlsx,iCasa/js-xlsx,kaktus40/js-xlsx