function validation(txtName,txtAddress,txtEmail)
{
      if(document.getElementById(txtName).value=="")
            {
                window.alert("Please Enter Name");
                document.getElementById(txtName).focus();
                return false;
            }
        else if(document.getElementById(txtAddress).value=="")
            {
                window.alert("Please Enter Address");
                document.getElementById(txtAddress).focus();
                return false;
            }                
        else if(document.getElementById(txtEmail).value=="")
            {
            window.alert("Please Enter Email");
            document.getElementById(txtEmail).focus();
            return false;
            }                
}