Learning JavaScript

Questions

1. Of the following identifiers, which are valid, which are not, and why?

   $someVariable
   _someVariable
   1Variable
   some_variable
   somèvariable
   function
   .someVariable
   some*variable

2. Convert the following identifiers using the conventions outlined in the first section of the chapter:

   var some_month;
   function theMonth // function to return current month
   current-month // a constant
   var summer_month; // an array of summer months
   MyLibrary-afunction // a function from a JavaScript package

3. Is the following string literal valid? If not, how would you fix it?

   var someString = ‘Who once said, “Only two things are infinite, the universe and human stupidity, and I’m not sure about the former.”’

4. Given a number, 432.54, what JavaScript returns the integer component of the number, and then finds the hexadecimal and octal conversion?

5. You create a JavaScript function in a library that can be used by other applications. A parameter, someMonth, is passed to the function. How would you determine whether it’s null or undefined?

Answers are provided in the appendix.