Check whether the process needs to go on; the user might have decided to page forward or backward, and it wouldn't do for the former page data to show up.
检查是否需要继续处理；用户可能决定向前或向后翻页，对于前面的页面数据不再处理。
2
The navigation bar contains controls to navigate forward and backward as well as the ability to enter a page to load directly.
导航条包含了可以向前向后或者直接定位页面的控件。
3
Zend_Paginator also takes care of generating the page navigation links, which allow the user to move forward and backward through the result set.