AllChars : Hello. Length : 5 H e l l o AllChars : HelloWorld. Length : 10 H e l l o W o r l d Got a exception. String.prototype.charAt: 'this' is null or undefined >> FirstChar : undefined Got a exception. String.prototype.charAt: 'this' is null or undefined >> FirstChar : 0 0 << FirstChar. >> FirstChar : 1.1 1 << FirstChar. >> FirstChar : 10 1 << FirstChar. >> FirstChar : Hello H << FirstChar. >> FirstChar : true t << FirstChar. >> FirstChar : false f << FirstChar. >> FirstChar : true t << FirstChar. >> FirstChar : [object Object] [ << FirstChar.