.Net魔法堂：史上最全的ActiveX开发教程——ActiveX与JS间交互篇

[Guid("0203DABD-51B8-4E8E-A1EB-156950EE1668")]
public partial class Uploader : UserControl, IObjectSafety
{
    public Uploader(){
    　　InitializeComponent();
　　}

    // 被JS调用的ActiveX方法
    public void SayHi(msg){
        MessageBox.show(msg);
    }
}

// 注意：object必须要写成<object></object>才能通过document.getElementById来获取
<object classid="clsid:xxxxxxxxxx" id="ax"></object>
<script type="text/javascript">
　　document.getElementById('ax').SayHi('Test');// 调用ActiveX方法
</script>

[ComImport,
 Guid("00000118-0000-0000-C000-000000000046"),
 InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
public interface IOleClientSite
 {
    void SaveObject();
    void GetMoniker(uint dwAssign, uint dwWhichMoniker, object ppmk);
    void GetContainer(out IOleContainer ppContainer);
    void ShowObject();
    void OnShowWindow(bool fShow);
    void RequestNewObjectLayout();
 }

[ComImport,
 Guid("0000011B-0000-0000-C000-000000000046"),
 InterfaceTypeAttribute(ComInterfaceType.InterfaceIsIUnknown)]
public interface IOleContainer
 {
    void EnumObjects([In, MarshalAs(UnmanagedType.U4)] int grfFlags,
     [Out, MarshalAs(UnmanagedType.LPArray)] object[] ppenum);
    void ParseDisplayName([In, MarshalAs(UnmanagedType.Interface)] object pbc,
     [In, MarshalAs(UnmanagedType.BStr)] string pszDisplayName,
     [Out, MarshalAs(UnmanagedType.LPArray)] int[] pchEaten,
     [Out, MarshalAs(UnmanagedType.LPArray)] object[] ppmkOut);
    void LockContainer([In, MarshalAs(UnmanagedType.I4)] int fLock);
 }

#region 调用js函数
        private Type typeIOleObject = null;
        private IOleClientSite oleClientSite = null;
        private IOleContainer pObj = null;

        /// <summary>
        /// 调用JS函数
        /// </summary>
        /// <param name="fnName">js函数名</param>
        /// <param name="args">入参</param>
        protected void CallJS(string fnName, params object[] args)
        {
            if (typeIOleObject == null)
            {
                typeIOleObject = this.GetType().GetInterface("IOleObject", true);
                object tmpOldClientSite = typeIOleObject.InvokeMember("GetClientSite",
                 BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.Public,
                null,
                this,
                null);

                oleClientSite = tmpOldClientSite as IOleClientSite;
                oleClientSite.GetContainer(out pObj);
            }

            //获取页面的Script集合
            IHTMLDocument pDoc2 = (IHTMLDocument)pObj;
            object script = pDoc2.Script;

            try
            {
                //调用JavaScript方法OnScaned并传递参数，因为此方法可能并没有在页面中实现，所以要进行异常处理
                script.GetType().InvokeMember(fnName,
                BindingFlags.Instance | BindingFlags.InvokeMethod | BindingFlags.Public,
               null,
                script,
                args);
            }
            catch { }
        }
        #endregion