ASP.net Page:
Pickup location: <input runat="server" id="inRadHome" checked type="radio" name="inRadioPickup" value="Home" />Home
Behind c# page :
if(condition)
{
string script_clinic = "<script type='text/javascript'>document.getElementById('inRadHome').value = 'Clinic'; document.getElementById('inRadHome').nextSibling.nodeValue = 'Clinic'; </script>";
ClientScript.RegisterStartupScript(this.GetType(), "ChangeInputValue", script_clinic);
}