我如何点击webbrowser上的按钮c＃

Question

<div class="Buttons">
  <button class="Button SemiRound Blue" id="SummonerRefreshButton" onclick="$.OP.GG.summoner.renewBtn.start(this, '1071306');" style="position: relative;">Yenile</button>
  <button class="Button SemiRound White" id="SpectateButton" onclick="$.OP.GG.summoner.openSpectator('gamesistemcom', '#ExtraView')">Live Game</button>
  <button class="Button SemiRound White" onclick="$.OP.GG.summoner.openMMR('gamesistemcom', '#ExtraView')">MMR'ı Kontrol Et</button>
  <button class="Button SemiRound White" onclick="$.OP.GG.summoner.openLpHistoryGraph('gamesistemcom', '#ExtraView');">Tier Graph</button>

string mmrDocument = "";
    private void Wb2_DocumentCompleted(object sender, WebBrowserDocumentCompletedEventArgs e)
    {
        wb2.Document.GetElementById("buttonID").InvokeMember("click");
        mmrDocument = wb2.DocumentText;
    }

如何点击“MMR'ıKontrolEt”按钮？ （这没有ID值）