判断鼠标是否移到某元素之外

jQuery代码:

例子说明：当鼠标移动至$("#test")之外时将$("#test")隐藏.

<script type="text/javascript">
        $(document).ready(function(){
            document.onmousemove = function() 
            {
                var m_move_x = event.pageX;   //鼠标X轴坐标
                var m_move_y = event.pageY;　　//鼠标Y轴坐标

                var div_top = $('#test').offset().top; 
                var div_left = $('#test').offset().left;
                var div_bottom = table_top + $('.exam_table').height();
                var div_right = table_left + $('.exam_table').width();

                if(m_move_x < table_left || m_move_x > table_right || m_move_y < table_top || m_move_y > table_bottom)
                {
                    $("#test").css("display", "none");
                }
            }
        });
    </script>