前台（写html的）的一个控件怎么在后台写？

有一控件在前台是写完可以使用的，但由于要使用动态生成控件，所以不能直接写html，要在后台写，请问怎么写。前台代码附下：
<style type="text/css">@import url( slider.css );
<TR id="fenid" runat="server">
<TD>
<table height="100%" width="100%">
<tr>
<td vAlign="top" noWrap align="right" width="50" bgColor="#ffffff"><asp:label id="lb_begin" runat="server"></asp:label></td>
<td noWrap align="left" bgColor="#ffffff">
<div>
<div id="sliderDemo1" style="HEIGHT: 40px" runat="server"></div>
</div>
<div id="sliderDetail" style="FONT-WEIGHT: bolder" align="center"></div>
</td>
<td vAlign="top" noWrap align="left" width="40" bgColor="#ffffff"><asp:label id="lb_end" runat="server"></asp:label></td>
</tr>
</table>
</TD>
</TR>

<script type="text/javascript">
//<![CDATA[
if (document.getElementById("sliderDemo1"))
{
var b=document.getElementById('comfort_lv').value/<%=fen_step%>-<%=fen_min%>
var sliderImage1 = new neverModules.modules.slider(
{targetId: "sliderDemo1",
sliderCss: "imageSlider1",
barCss: "imageBar1",
min: 0,
max: <%=fen_max%>,
ckValue:10,
hints: "拉动滑竿改变设置"
});
//alert(sliderImage1)

sliderImage1.onchange = function () {
getElementById("sliderDetail").innerHTML = "";
};

sliderImage1.onend = function () {
//getElementById("sliderDetail").innerHTML += ", onend: The end the sliderImage1 value is " +sliderImage1.getValue();
getElementById("comfort_lv").value = (sliderImage1.getValue()+<%=fen_min%>)*<%=fen_step%>;
}

sliderImage1.create();
sliderImage1.setValue(b);

}

</script>


各位有哪里看不明白的我再解释，谢谢，解决马上给分