addClass doesn't fail when passed an undefined or null variable (#1309)
addClass doesn't fail when passed an undefined or null variable (#1309)

demetr84/Jquery,roytoo/jquery,ilyakharlamov/jquery-xul,RubyLouvre/jquery,roytoo/jquery,diracdeltas/jquery,quiaro/request-agent,mislav/jquery,hoorayimhelping/jquery,npmcomponent/component-jquery,jcutrell/jquery,rwaldron/jquery,isaacs/jquery,fat/jquery,scottjehl/jquery,kpozin/jquery-nodom,diracdeltas/jquery,jcutrell/jquery,mislav/jquery,gnarf/jquery,dtjm/jquery,jquery/jquery,praveen9102/Shazam,Karyotyper/jquery,eburgos/jquery,sancao2/jquery,npmcomponent/component-jquery,ilyakharlamov/jquery-xul,batiste/jquery,Karyotyper/jquery,fat/jquery,scottjehl/jquery,rwaldron/jquery,isaacs/jquery,sancao2/jquery,jquery/jquery,eburgos/jquery,chitranshi/jquery,hoorayimhelping/jquery,RubyLouvre/jquery,diracdeltas/jquery,demetr84/Jquery,roytoo/jquery,kpozin/jquery-nodom,eburgos/jquery,praveen9102/Shazam,gnarf/jquery,batiste/jquery,jquery/jquery,chitranshi/jquery,sancao2/jquery,Karyotyper/jquery,dtjm/jquery