js调用后台初始原来的数据，并且可以出示为特定的值，此处为“河南省”
<script type="text/javascript"> function show()
{
set_school_pos('河南省','<%=ClassCity%>','<%=ClassArea%>')
} </script>html主要代码如下：
<head><script type="text/javascript" src="/js/city/regions.js" charset="gb2312"></script> <script type="text/javascript" src="/js/city/school_register.js"></script></head><body onload="show()" > <form id="form1" name="form1" runat="server"><select name="sch_province" onChange="javascript:set_school_pos(this.value);"> <option value="">省份</option> </select> <select name="sch_capital" onChange="javascript:set_school_pos(document.form1.sch_province.value,this.value);"> <option value="">地级市</option> </select> <select name="sch_city"> <option value="">市、县级市、县</option> </select></frome></body>后台代码：
private ClassSkyClass _ClassSkyClass=new ClassSkyClass();public string ClassCity
{ get { return _ClassSkyClass.City; } }
public string ClassArea { get { return _ClassSkyClass.Area; } }