Add some comment to explain what is it.
Add some comment to explain what is it.

Ju2ender/JavaScript-Exercise,Ju2ender/JavaScript-E,Ju2ender/JavaScript-E,Ju2ender/JavaScript-Exercise,Ju2ender/JavaScript-E,Ju2ender/JavaScript-Exercise,Ju2ender/JavaScript-E,Ju2ender/JavaScript-Exercise