animate和scrollTop实现自动滚屏

function _scrollHandler(){
		var nScrollTop = jContent.scrollTop(),
		nMaxHeight = jContentBody.outerHeight(true),
		nScreenHeight = jContent.height(),
			
		nNext = nScrollTop + nScreenHeight;
			
		if(nNext >= nMaxHeight){
			nNext = 0;
		}
		
		// 页面滚屏操作。
		jContent.animate({
			scrollTop: nNext
		}, 滚动时间间隔：自己设定);
	}