How Inject Javascript code into webpage and receive a return value

[AlexanderG84]

I can't understand how to inject a javascript code into the web page. Also how could I get a possible return from this script. I loaded the MasterDevs.ChromeDevTools Solution in C#.

Thanks

[ststeiger]

string javaScriptToExecute = @"document.getElementById(""result"").innerHTML";

CommandResponse<EvaluateCommandResponse> evalResponse = await chromeSession.SendAsync(new EvaluateCommand
{
    Expression = javaScriptToExecute,
    // ContextId = 123
});

if (evalResponse.Result.ExceptionDetails != null)
    System.Console.WriteLine(evalResponse.Result.ExceptionDetails);
else
    System.Console.WriteLine(evalResponse.Result.Result.Value);

[AlexanderG84]

Thank you very much Ststeiger! Works well! But If I wanted to see the web page on chrome and the impact of javascript on the page, is it possible? first i set an index in every tag( with a script), and after, i set border color only for some index( with inject a second script).

TY

[ststeiger]

Sure, you can screenshot the page.

Full code in the sample program: https://github.com/MasterDevs/ChromeDevTools/blob/master/source/Sample/Program.cs

If you need to wait a little after the functions executed:

// System.Threading.Thread.Sleep(waitInterval);
await System.Threading.Tasks.Task.Delay(waitInterval);

[AlexanderG84]

thanks for the answer. I'm already using the example code. But my idea is the interact with the browser and see the page in "realtime". while browsing normally on chrome, I would like to be able to send scripts with external buttons from the browser. For example, while browsing the chrome tab, I wish I could press a key that colors all the "form" tags. it's possible? sorry if i wasn't clear