Check the window type — practice exercise

What you'll be asked to do

1. 1.Check the window typeexercise · easy · 10 min

   Report the type of the window object.

   Passes when: #out should show object.

2. 2.Show a var attaches to windowexercise · easy · 10 min · practice plan

   Declare a global var and read it from window.

   Passes when: #out should show 5.

3. 3.Show let does not attachexercise · easy · 10 min · practice plan

   Declare a let and show window does not have it.

   Passes when: #out should show not on window.

4. 4.Read the viewport widthexercise · easy · 10 min · practice plan

   Report whether the window has a positive width.

   Passes when: #out should show positive.

5. 5.Check for alertexercise · medium · 10 min · practice plan

   Report the type of window.alert.

   Passes when: #out should show function.

6. 6.Fix var expected to stay off windowbug fix · easy · 8 min

   var does attach to window, unlike let.

   Passes when: #out should show on window.

7. 7.Fix the wrong case used for a global functionbug fix · easy · 8 min · practice plan

   JavaScript names are case sensitive, and setTimeout is not the same as setTimeOut.

   Passes when: #out should show function.

8. 8.Fix the var read before it existsbug fix · easy · 8 min · practice plan

   The variable is read on the line above where it is declared.

   Passes when: #out should show 5.

9. 9.Fix the width compared to a non-numeric stringbug fix · easy · 8 min · practice plan

   Comparing a number against text that is not numeric coerces to NaN, and any comparison with NaN is false.

   Passes when: #out should show positive.

10. 10.Fix document compared to the wrong windowbug fix · easy · 8 min · practice plan

    document belongs to this window, not to a freshly built object.

    Passes when: #out should show same document.

Between them these tasks cover window, Global scope and var vs let.

Looking for a different chapter? See every practice set, or switch to the interview theory questions.