Using this code to load the website

Code:
 Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
          WebControl1.Source = New System.Uri("https://login.yahoo.com/config/login")
And this code to submit the value to html textbox1

Code:
 Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
  WebControl1.ExecuteJavascript("document.getElementById('login-text').value=" + TextBox1.Text)
Code:
The textbox with id (login-text) work fine but the other one ( pass ) always get empty ?