Fix spec on IE < 9
Fix spec on IE < 9

youprofit/knockout,JesseQin/knockout,ErikSchierboom/knockout,pianove/knockout,martijnwetering/knockout,hitesh97/knockout,cgourlay/knockout,getshuvo/knockout,mattbalmer/knuckles,cgourlay/knockout,youprofit/knockout,DekeYan/knockout,skyh/knockout,brianmhunt/knockout,xeronith/knockout,brianmhunt/knockout,Sir0xb/knockout,gwokudasam/knockout,bago/knockout,stonegithubs/knockout,getshuvo/knockout,JesseQin/knockout,DekeYan/knockout,xeronith/knockout,moonpyk/knockout,moonpyk/knockout,hitesh97/knockout,Sir0xb/knockout,martijnwetering/knockout,pianove/knockout,bago/knockout,ErikSchierboom/knockout,mattbalmer/knuckles,stonegithubs/knockout,gwokudasam/knockout,skyh/knockout