checkbox checked issue..

[u0224078]

I click a checkbox ,it is checked but when i change to page 2 ,the checkbox still checked....
have any way to solve it??

                <thead>
                <tr>    
                    <th class="sortable">
                        <input type="checkbox" ng-model="checkmaster" >
                    </th>
                    <th sortable="code" class="sortable">
                        Order #
                    </th>
                    <th sortable="placed" class="sortable">
                        Date Placed
                    </th>
                    <th class="st-sort-disable th-dropdown">
                        <select class="form-control width-15"
                                filter-by="statusDisplay"
                                filter-type="select"
                                ng-model="status"
                                ng-change="filter()">
                            <option value="">All Statuses</option>
                            <option ng-repeat="option in statusOptions track by option.value"
                                    value="{{option.value}}">{{option.text}}
                            </option>
                        </select>
                    </th>
                    <th sortable='total.value' class="sortable">
                        Total
                    </th>
                </tr>
                </thead>
                <tbody>
                <tr grid-item>
                <td width="1%"><input type="checkbox"  name="foo" ng-checked="checkmaster" value="{{item.code}}"></td>
                   <td width="30%" ng-bind="item.code"></td>
                    <td width="30%" ng-bind="item.code"></td>
                    <td width="30%" ng-bind="item.placed | date:'MM/dd/yyyy'"></td>
                    <td ng-bind="item.statusDisplay"></td>
                    <td ng-bind="item.total.formattedValue"></td>
                </tr>
                </tbody>