function AtLeastOneContactNo_ClientValidate(source, args)
{
    var ContactNo = document.getElementById("ctl00_ContentPlaceHolder1_crContactDetails_txtAreaCode").value + document.getElementById("ctl00_ContentPlaceHolder1_crContactDetails_txtTelNumber").value;
    var WorkNo = document.getElementById("ctl00_ContentPlaceHolder1_crContactDetails_txtWorkArea").value + document.getElementById("ctl00_ContentPlaceHolder1_crContactDetails_txtWorkTel").value;
    var CellNo = document.getElementById("ctl00_ContentPlaceHolder1_crContactDetails_txtCell").value;
    
    if (ContactNo == "" && CellNo == "" && WorkNo == "")
        args.IsValid = false;
    else
        args.IsValid = true;            
}