what are the values of thirdVar, fourthVar and fifthVar after these lines of javascript have been executed.

Code:
var firstVar = 'Joseph' ;
var secondVar = ' Locke' ;
var thirdVar = firstVar.charAt (0) + '. ' + secondVar;
var fourthVar = thirdVar.length;
var = 'The last character is' + thirdVar.charAt(fourthVar) + ' ! ' ;