conversion from v5 to v8 ?? any help ?? very simple

hi everyone

I have found I code that I need to use it on my website. Unfortunately this script is version 5 and if I export the movie as v5 then every thing is ok. if I export ti as flash v8 the script dosen't work. can anyone tell me how should be changed to work ??

/// the flash can contain one frame only with this code

Movieclip.prototype.elasticScale = function(target, accel, convert) {
xScale = xScale * accel + (target - this._xscale) * convert
yScale = yScale * accel + (target - this._yscale) * convert
this._xscale += xScale
this._yscale += yScale
}

// end --->

// this code is atached to an movieclip named as you whant

onClipEvent (enterFrame) {
if (this.hitTest(_root._xmouse,_root._ymouse,true)) {
elasticScale(150, 0.9, 0.1)
} else {
elasticScale(100, 0.9, 0.1)
}
}

//


thank you very much !