webBrowser中为html控件赋值及调用js[vb.net]

<asp:HiddenField ID="H_str" runat="server" />            <script type="text/javascript">                function PlayFlv() {                    var H_name = document.getElementById("H_str");                   var str = H_name.value;                   var s1 = new SWFObject("cb.swf", "CuPlayer", "100%", "100%", "9", "#000000");                   s1.addParam("allowfullscreen", "true");                   s1.addParam("allowscriptaccess", "always");                   s1.addParam("wmode", "opaque");                   s1.addParam("quality", "high");                   s1.addParam("salign", "lt");                   s1.addVariable("CuPlayerFile", str);                   //s1.addVariable("CuPlayerImage", "Images/flashChangfa2.jpg");                   s1.addVariable("CuPlayerShowImage", "true");                   s1.addVariable("CuPlayerWidth", "640");                   s1.addVariable("CuPlayerHeight", "480");                   s1.addVariable("CuPlayerAutoPlay", "true");                   s1.addVariable("CuPlayerAutoRepeat", "true");                   s1.addVariable("CuPlayerShowControl", "true");                   s1.addVariable("CuPlayerAutoHideControl", "false");                   s1.addVariable("CuPlayerAutoHideTime", "3"); //默认3                   s1.addVariable("CuPlayerVolume", "75"); //默认75                   s1.write("player1");                 }             </script>

这是网页中的代码,用来播放flv文件,然后在winform中加载这个网页.调用playflv,

        Dim fname As String = Main.Filename        Dim a As HtmlElement        Try            wb_file.Navigate(url)            a = wb_file.Document.GetElementById("H_str")            a.SetAttribute("value", fname)            wb_file.Document.InvokeScript("PlayFlv")        Catch ex As Exception            MsgBox(ex.Message)        End Try

vb中的代码不能放在load事件中执行.不然提示出错.

 wb_file.Navigate(url)

这句本是写在load事件中的,别的我写到timer中了.