private void Button_Clicked(object sender, EventArgs e) { flag = !flag; string pausefunctionString = @"var videos = document.querySelectorAll('video'); [].forEach.call(videos, function(video) { video.pause(); }); "; string playfunctionString = @"var videos = document.querySelectorAll('video'); [].forEach.call(videos, function(video) { video.play(); }); "; if (flag) { MyWebView.Eval(pausefunctionString); } else { MyWebView.Eval(playfunctionString); } }