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<style id="Style1" type="text/css" runat="server">
.cs
{
background-color:Window;
}
.cs1
{
background-color:ButtonFace;
}
</style>
<script type="text/javascript">
function mov()
{
var btnid= document.getElementById('btn1');
btnid.className='cs';
}
function mout()
{
var btnid= document.getElementById('btn1');
btnid.className='cs1';
}

</script>
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<input type="button" id="btn1" value="Change" onmouseover="mov()" onmouseout="mout()" runat="server" onclick="return btn1_onclick()" />
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