JavaScript30 is 30-day vanilla javaScript coding challenge by Wes Bos (@wesbos). The purpose of these posts is to reflect my troubles and moments of ahhaa. Lessons from Day 10: Demo - Day 10

1. let var - another type of variable in JavaScript. Variables declared by let have as their scope the block in which they are defined, as well as in any contained sub-blocks . In this way, let works very much like var. The main difference is that the scope of a var variable is the entire enclosing function—MDN link
2. inBetween = !inBetween is same as inbetween = true. It's also called a flag variable - a flag variable, in its simplest form, is a variable you define to have one value until some condition is true, in which case you change the variable's value.
3. Warning‐change vs click I started it by myself and in this point - it didn't react anyhow.

   if(e.shiftKey && this.checked){
   	console.log("jep");
   }
   
   

   As I listened to the 'change', I changed it to 'click' and voila - it worked.

Day 10 code on github.