/**
* @author LiLin
* 使用方法：    
    var sa = new ScrollAction($('.noticeList'), 'li', 1, true);
    sa.start();
*/

    function ScrollAction(listObj, listElem, speed, isSeries) {	//listObj为需要滚动的列表，  speed为滚动速度
        var pos, top, aniTop, height, left, aniLeft;
        var id = '';  //记录setInterval的标记id
        pos = listObj.position();
        top = pos.top; 		//列表的top
        aniTop = top; 			//记录当前运动时的top
        left = pos.left;
        aniLeft = left;
        height = listObj.height(); //列表的高度
        width = listObj.width()

        var scrollLeft = function() {
            aniLeft--;
            if (!isSeries) {	//isSeries变量控制是否连续滚动，false不连续，true连续
                if (aniLeft == -width) {	//不连续，滚动玩重新滚动
                    listObj.css({ 'left': left });
                    aniLeft = left;
                };
            } else {
                if (aniLeft == -listObj.children().eq(0).width()) {	//连续滚动
                    var firstItem = '<' + listElem + '>' + listObj.children().eq(0).html() + '</' + listElem + '>';
                    listObj.children().eq(0).remove();
                    listObj.append(firstItem);
                    aniLeft = 6;
                };

            };
            listObj.css({ 'left': aniLeft + 'px' });
        };

        var hover = function(id) {
            listObj.hover(function() {
                clearInterval(id);
            }, function() {
                id = setInterval(scrollLeft, speed);
            });
        };

        this.start = function() {
            id = setInterval(scrollLeft, speed);
            hover(id);
        };
    };