<!doctype html><htmlclass="reftest-wait"><head><title> Bug 1216842: effect-level easing function produces negative values passed to step-end function (compositor thread)</title><style>#target{width:100px;height:100px;background:blue;}</style></head><body><divid="target"></div></body><script>vartarget=document.getElementById("target");vareffect=newKeyframeEffect(target,{opacity:[0,1],easing:"step-end"},{fill:"forwards",/* The function produces negative values in (0, 0.766312060) */easing:"cubic-bezier(0,-0.5,1,-0.5)",duration:100,iterations:0.75/* To finish in the extraporation range */});varanimation=newAnimation(effect,document.timeline);animation.play();animation.finished.then(function(){document.documentElement.className="";});</script></html>