function validateInput()
{
    var name="";
    var phone="";
    var timeOfCall="";
    
    name = document.getElementById('ctl00_ContentPlaceHolder1_txtName').value;
    phone = document.getElementById('ctl00_ContentPlaceHolder1_txtContactNo').value;
    timeOfCall = document.getElementById('ctl00_ContentPlaceHolder1_txtPreferredTime').value;
        
    if(name == "")
    {
        alert('Please enter Name');
        return false;
    }
    else if(phone == "")    
    {
        alert('Please enter Contact No');
        return false;
    }
    else if(timeOfCall == "")
    {
        alert('Please enter Preferred time of call');
        return false;
    }
    else
    return true;
}