fixed errors & undefined references.
fixed errors & undefined references.

girldevelopit/gdi-featured-js-intro,amandagogogo/gdicincy-intro-js,jennifer-mann/gdi-intro-javascript,Roenok/gdi-intro-javascript,anythingcodes/gdi-featured-js-intro,Roenok/gdi-intro-javascript,jennifer-mann/gdi-intro-javascript,girldevelopit/gdi-featured-js-intro,amandagogogo/gdicincy-intro-js,anythingcodes/gdi-featured-js-intro