user control in ASP.NET

Create A property inside your User Control Like this

public string mySelectedValue
{
  get
  {
     return ddlControl1.SelectedValue.toString();
  }
}

access the property in your page where you are using the UserControl like

string strValue = UserControl1.mySelectedValue;

If you want to access the control at Client end (inside Javascript/jQuery), do the following

protected void Page_Load(object sender, EventArgs e)
{
    ClientScript.RegisterStartupScript("strCtrlID","'" + ddlCtrl.ClientID + "'");
    //Rest of your page load logic.
}

document.getElementById(strCtrlID); 

cheaars :)