Is JavaScript's array.clear() not a function?

I'm trying to empty an array containing my drawn coordinates when a button "clear" is pressed.

When I call drawnDivs.clear(), I get an error that it is not a function. drawnDivs is certainly an array, and I have Firebug console.logs printing things out. It's hosted here.

Answer

Nope, it's not. But drawnDivs.length = 0 should work.