cefsharp 执行 js 并返回结果

private async void button1_Click(object sender, EventArgs e)
{
    var response = await browser.EvaluateScriptAsync("document.title");
    if (response.Success)
        MessageBox.Show(response.Result?.ToString());

    response = await browser.EvaluateScriptAsync("function add(a,b){ return a + b; }");
    response = await browser.EvaluateScriptAsync("add(2,3)");
    if (response.Success)
        MessageBox.Show(response.Result?.ToString());
}