Code:

private void Form1_Load(object sender, System.EventArgs e)
        {
                                      scriptEngine = new ScriptControlClass();
            scriptEngine.Language = "JScript";

            scriptEngine.AddObject("frm", this, true);
            //scriptEngine.AddObject("tst", test1, true);
                                      //blabla
        }

public void hello(string msg) {
            MessageBox.Show("MSG:c#: " + msg);
        
        }

private void button1_Click(object sender, System.EventArgs e)
        {
            lblError.Text = "";
            try 
            {
                      scriptEngine.ExecuteStatement(tbScript.Text);
            } 
            catch (Exception exc) {
                      lblError.Text = exc.Message;
            }
        }

Code:
frm.hello(' ,Ivane!');