can't use mouse wheel to control slider knob in some browser

Steps to Reproduce

<zk>
<div height="400px">
<slider id="knob1" mold="knob" minpos="0.0" maxpos="100.0" curpos="80.0" step="0.5" angleArc="360" strokeWidth="10"/>
</div>
</zk>
open the case with Firefox(or IE).
move your cursor onto the slider knob.
Try to change the value of slider knob using mouse wheel.

Current Result

value won't change

Expected Result

value should change