how to stop function execution

i m using a function to scroll the text vertically
<img src="images/btn-dn" onMouseOver="InitScripts();">
i m starting its execution onMouseOver
how can i stop its execution onMouseOut

<img src="images/btn-dn" onmouseover="InitScripts();" onmouseout="StopScripts();" />

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i m using a code to display vertical scroller on my page and this fucntion starts scrolling
function InitScripts(){
zxcVScroller('data1',[1000,100,1]);
}
on mouse over

now i want to stop its execution on mouse out