<script type="text/javascript">
function validateCheckBoxes()
{
//debugger;
var isValid = false;
var gridView = document.getElementById('<%=GRD_viewoverview.ClientID%>');
for (var i = 1; i < gridView.rows.length; i++) {
var inputs = gridView.rows[i].getElementsByTagName('input');
if (inputs != null) {
if (inputs[0].type == "checkbox") {
if (inputs[0].checked) {
isValid = true;
return true;
}
}
}
}
alert("Please select atleast one checkbox for Item Transfer");
return false;
}
</script>


<asp:Button ID="btn_rentalcon" runat="server" Text="Create Rental Contract" Width="153px" OnClientClick="return validateCheckBoxes();" OnClick="btn_rentalcon_Click" /></td>