Update controllers.js
Merge pull request #10 from ChrisBoesch/master

update
sloved the beginner path not shown problem
Merge pull request #252 from LI-HE/master

sloved the beginner path not shown problem
Update practice.html
Merge pull request #253 from ruijunhuang2010/master

Merge pull request #22 from ChrisBoesch/master
Merge pull request #23 from ChrisBoesch/master

update