Execute Javascript cannot Creates variable?

hallo everyone, I Typed var player = GetPlayer() in Execute javascript. I ran my published SL project as HTML and opened it on Google Chrome. than I got actionator::exeJavaScript - this.execUserJs is not a function on consol.log. I tried to type player on consol then I got this Uncaught ReferenceError: player is not defined
at <anonymous>:1:1

in other hand, if I type alert() function on Execute JS, it will work. so my conclusion is I can't creat any Variable on Execute JS trigger...

I also tried to creat variable in browser console, and call GetPlayer object. it works fine

I am using AS3.