public class ClientScript:System.Web.UI.WebControls.WebControl
{
   protected override void OnPreRender(EventArgs e)
   {
     if (this.Page != null) {
       ClientScriptManager manager = this.Page.ClientScript;
       //注册资源脚本
       manager.RegisterClientScriptResource(typeof(ClientScript),"JsControl.JScript.js");
     }
     base.OnPreRender(e);
   }
}

<%@Register Assembly="JsControl" Namespace="JsControl" TagPrefix="zhi" %>
<zhi:ClientScript runat="server" ID="rs1" />