/**
			基本思路：两张div重叠显示，一张以透明1显示图片，一张渐变显示图片
			
			第一步focus_show设置为显示第一张图片且透明图为0
			第二步缓慢增加至接近1(ie为100)
			第三步focus_bg显示第一张图片并停顿一段时间
			重复以上步骤
		*/

		(function($){
			
			$.fn.defaultsettings = {
					focus_id : 1,			//待显示图片
					focus_time : 0,
					focus_begin : true,		//第一张图片装载后后变为false
					
					focus_count : 0,		//图片队列的长度
					focus_bg : "",			//
					focus_url : "",			//图片url
					focus_title : "",		//图片title
					
					focus_left_bg : "",
					focus_left_show : "",
					focus_right_bg : "",
					focus_right_show : "",
					
					stop_time : 5000,
					opacity_step : 5,		//1<=opacity_step<20	
					isuselink : true,
					isusearrow : true,		//
					color0 : "#fff",		//小方块非选中状态的颜色
					color1 : "#333",
					width : 1200,			//图片原始宽度
					height : 400,			//图片原始高度
					realwidth : 1500,
					realheight : 500
			};
			
			
			$.fn.run = function(options){
				var setting = $.extend({}, $.fn.defaultsettings, options);
				
				var focus_interval;			//定时器
				
				var $this = $(this);
				
				var offset = $('#focus').offset();
				
				init = function(){
					//确定长度
					if(navigator.appname == "microsoft internet explorer"){
						setting.focus_count = document.getelementbyid("focus_img").childnodes.length;
					}else{
						setting.focus_count = document.getelementsbyname("focus_img").length;
					}
					
					
					//增加链接
					if(setting.isuselink){
						$('#focus_link').append("<ul></ul>");
						$('#focus_link').css('width', setting.focus_count*30);
						for(var i=1; i<=setting.focus_count; i++){
							$('#focus_link ul').append("<li id='li_" + i + "'><div style='width:8px;height:8px;border:1px solid gray;cursor:pointer;border-radius:8px;'></div></li>");
						}
						$('#focus_link').css('position', 'absolute');
						$('#focus_link ul li').css('margin-left', '10px');
						$('#focus_link ul li').css('float', 'left');
						
						$('#focus_link div').bind('click', jumpto);
						//窗口大小变化时重新定位$('#focus_link')
						$(window).resize(relocatelink);
						
						relocatelink();
					}
					
					if(setting.isusearrow){
						
						$('.control').bind('mouseenter', control_mouseenter);
						$('.control').bind('mouseleave', control_mouseleave);
						$('#to-left').bind('click', control_toleft);
						$('#to-right').bind('click', control_toright);
						
						$('#focus').bind('mouseenter', function(){$('.control').css('display', 'block');});
						$('#focus').bind('mouseleave', function(){$('.control').css('display', 'none');});
						
						//窗口大小变化时重新定位$('#focus_link')
						$(window).resize(relocatearrow);
						
						relocatearrow();
					}
					
					$(window).resize(windowresize);
				};
			
				func_focus = function(){
					if(setting.focus_id > setting.focus_count) setting.focus_id = 1;
					//取消定时器.
					if(!setting.focus_begin) {
						clearinterval(focus_interval); 
					}
					
					//启动定时器
					focus_interval = setinterval("focus_showimg()", 50);
				};
			
				update_link = function(index){
					if(setting.isuselink){
						$('#focus_link div').css('background-color', setting.color0);
						//如果不设置font-size为0，每次修改背景设置时ie6会将font-size设置为浏览器默认值将div撑开(此处写在了css样式里)
						//$('#focus_link div').css('font-size', 0);
						$("#focus_link li[id='li_"+(index==0?setting.focus_count:index)+"'] div").css('background-color', setting.color1);
					}
				};
			
				jumpto = function(){
					var lid = $(this).parent().attr("id");
					var rid = lid.substring(lid.lastindexof('_')+1);
					
					setting.focus_id = parseint(rid);
					setting.focus_time = 0;
					setting.focus_begin = true;
					setting.focus_bg = "";
					
					clearinterval(focus_interval); 
					settimeout(func_focus, 50); 
				};
				
				control_mouseenter = function(){
					$(this).removeclass('opacity_class0');
					$(this).addclass('opacity_class1');
				};
				
				control_mouseleave = function(){
					$(this).addclass('opacity_class0');
					$(this).removeclass('opacity_class1');
				};
			
				control_toleft = function(){
					var go = setting.focus_id - 3;
					go = go==0?setting.focus_count:go;
					go = go<0?setting.focus_count-1:go;
					
					$("#focus_link li[id='li_"+go+"'] div").click();
				};
				
				control_toright = function(){
					var go = setting.focus_id - 1;
					
					$("#focus_link li[id='li_"+go+"'] div").click();
				};
				
				//使用focus_show名称在ie下报错，难道是因为页面有一个id为focus_show的div吗
				focus_showimg = function(){
					if(setting.focus_id > setting.focus_count) setting.focus_id = 1;
					if(setting.focus_time < 100 /setting.opacity_step && setting.focus_bg != "")
					{
						var v = setting.opacity_step;
						if(navigator.appname=="microsoft internet explorer")
						{
							document.getelementbyid("focus_show").style.filter = "alpha(opacity=" + (v * setting.focus_time) + ")";
							document.getelementbyid("focus_left_show").style.filter = "alpha(opacity=" + (v * setting.focus_time) + ")";
							document.getelementbyid("focus_right_show").style.filter = "alpha(opacity=" + (v * setting.focus_time) + ")";
						}else{
							document.getelementbyid("focus_show").style.opacity = v * setting.focus_time / 100;
							document.getelementbyid("focus_left_show").style.opacity = v * setting.focus_time / 100;
							document.getelementbyid("focus_right_show").style.opacity = v * setting.focus_time / 100;
						}
						setting.focus_time ++;
					}else if(setting.focus_count > 0){//图片队列不为空
						if(!setting.focus_begin)
						{	
							document.getelementbyid("focus_bg").innerhtml = "<img src='" + setting.focus_bg + "' width='" + setting.realwidth + "' height='" + setting.realheight + "'/>";
							$(document.getelementbyid("focus_left_bg")).css('background', "url(" + setting.focus_left_bg + ") repeat-x");
							$(document.getelementbyid("focus_right_bg")).css('background', "url(" + setting.focus_right_bg + ") repeat-x");
							setting.focus_time = 0;
							clearinterval(focus_interval);
						}
						var val = document.getelementbyid("focus_" + setting.focus_id).innerhtml;
						var val_left = document.getelementbyid("focus_left_" + setting.focus_id).innerhtml;
						var val_right = document.getelementbyid("focus_right_" + setting.focus_id).innerhtml;
						var arr = val.split("|");
						if(navigator.appname=="microsoft internet explorer")
						{
							document.getelementbyid("focus_show").style.filter = "alpha(opacity=0)";
							document.getelementbyid("focus_left_show").style.filter = "alpha(opacity=0)";
							document.getelementbyid("focus_right_show").style.filter = "alpha(opacity=0)";
						}else{
							document.getelementbyid("focus_show").style.opacity = 0;
							document.getelementbyid("focus_left_show").style.opacity = 0;
							document.getelementbyid("focus_right_show").style.opacity = 0;
						}
						document.getelementbyid("focus_show").innerhtml = "<a href='" + setting.focus_url + "' target='_blank' title='" + setting.focus_title + "'><img src='" + arr[0] + "' width='" + setting.realwidth + "' height='" + setting.realheight + "'/></a>";
						
						$(document.getelementbyid("focus_left_show")).css('background', "url(" + val_left + ") repeat-x");
						$(document.getelementbyid("focus_right_show")).css('background', "url(" + val_right + ") repeat-x");
						setting.focus_left_show = val_left;
						setting.focus_right_show = val_right;
						setting.focus_url = arr[1];
						setting.focus_title = arr[2];
						if(setting.focus_count > 1) setting.focus_id ++;
						if(!setting.focus_begin) {
							focus_interval = setinterval("func_focus()", setting.stop_time); 
							update_link(setting.focus_id-2);
						}else 
							setting.focus_begin = false;
						setting.focus_bg = arr[0];
						setting.focus_left_bg = val_left;
						setting.focus_right_bg = val_right;
					}
				};
				
				windowresize = function(){
					//$('#focus_bg').css('width','100%');
					//$('#focus_show').css('width','100%');
					$('#focus_bg').css('width',0);
					$('#focus_show').css('width',0);
					
					//图片高度不变
					//var availwidth = screen.availwidth;
					var clientwidth = document.documentelement.clientwidth;
					var scrollwidth = $('body').get(0).scrollwidth;
					if(scrollwidth==clientwidth && clientwidth>=setting.width){
						//1.屏幕大于图片时不拉伸
						setting.realwidth = setting.width;
						setting.realheight = setting.height;
						var left_fg_width = (clientwidth-setting.width)/2;
						//调整中间图片大小和位置
						$('#focus_bg').css('left', left_fg_width);
						$('#focus_show').css('left', left_fg_width);
						$('#focus_bg').css('width', setting.realwidth);
						$('#focus_show').css('width', setting.realwidth);
						
						//设置两边背景色的宽度、高度和位置
						$('#focus_left_bg').css('left', 0);
						$('#focus_left_bg').css('width', left_fg_width);
						$('#focus_left_bg').css('height', setting.realheight);
						$('#focus_left_show').css('left', 0);
						$('#focus_left_show').css('width', left_fg_width);
						$('#focus_left_show').css('height', setting.realheight);
						
						$('#focus_right_bg').css('left', (clientwidth+setting.width)/2);
						$('#focus_right_bg').css('width', left_fg_width);
						$('#focus_right_bg').css('height', setting.realheight);
						$('#focus_right_show').css('left', (clientwidth+setting.width)/2);
						$('#focus_right_show').css('width', left_fg_width);
						$('#focus_right_show').css('height', setting.realheight);
						
						
						//2.屏幕大于图片时拉伸图片
						//setting.realwidth = clientwidth;
						//setting.realheight = clientwidth/setting.width*setting.height;
					}else if(scrollwidth==clientwidth && clientwidth<setting.width){
						
						//1.图片高度始终不变
						setting.realwidth = setting.width;
						setting.realheight = setting.height;
						var left_fg_width = (clientwidth-setting.width)/2;
						
						$('#focus_bg').css('left', left_fg_width);
						$('#focus_show').css('left', left_fg_width);
						$('#focus_bg').css('width', setting.realwidth + left_fg_width);
						$('#focus_show').css('width', setting.realwidth + left_fg_width);
						
						$('#focus_left_bg').css('width', 0);
						$('#focus_left_show').css('width', 0);
						$('#focus_right_bg').css('width', 0);
						$('#focus_right_show').css('width', 0);
						
						//2.缩放图片
						//setting.realwidth = clientwidth;
						//setting.realheight = clientwidth/setting.width*setting.height;
					}else{
						
						//1.图片高度始终不变
						setting.realwidth = setting.width;
						setting.realheight = setting.height;
						var left_fg_width = (scrollwidth-setting.width)/2;
						
						$('#focus_bg').css('left', left_fg_width);
						$('#focus_show').css('left', left_fg_width);
						$('#focus_bg').css('width', scrollwidth - left_fg_width);
						$('#focus_show').css('width', scrollwidth - left_fg_width);
						
						$('#focus_left_bg').css('width', 0);
						$('#focus_left_show').css('width', 0);
						$('#focus_right_bg').css('width', 0);
						$('#focus_right_show').css('width', 0);
						
						//2.缩放图片
						//setting.realwidth = scrollwidth;
						//setting.realheight = scrollwidth/setting.width*setting.height;
					}
					//修改当前图片的大小
					$('#focus_bg img').css('height', setting.realheight);
					$('#focus_bg img').css('width', setting.realwidth);
					$('#focus_show img').css('height', setting.realheight);
					$('#focus_show img').css('width', setting.realwidth);
					
					$('#focus').css('height', setting.realheight);
					
				};
				
				relocatelink = function(){
					offset = $('#focus').offset();
					$('#focus_link').css('left', (offset.left + $('#focus').width()*1/2 -$('#focus_link').width()/2)+'px');
					$('#focus_link').css('top', (offset.top + $('#focus').height()*4/5)+'px');
				};
				
				relocatearrow = function(){
					offset = $('#focus').offset();
					$('#to-left').css('left', (offset.left+50) + 'px');
					$('#to-left').css('top', (offset.top+$('#focus').height()/2-$('#to-left').height()/2) + 'px');
					
					$('#to-right').css('left', (offset.left+$('#focus').width()-$('#to-left').width()-50) + 'px');
					$('#to-right').css('top', (offset.top+$('#focus').height()/2-$('#to-left').height()/2) + 'px');
				};
				
				return this.each(function(){
					//先初始化#focus大小，图片大小，再初始化链接和arrow位置
					windowresize();
					init();
					func_focus();
				});
				
				
				
			};
			
			
			
		})(jquery);