(function ($){
	/**
	* @author 鲁振兴
	* 弹出层
	* v1.04
	* v1.04 2011-10-19 修改：IE6下关闭窗口解除滚动事件时，只解除dialog里的滚动定位事件
	* v1.03 2011-9-21 修改：如果对象不存在则直接退出函数
	* $('div').dialog();
	**/
	$.fn.dialog = function (isfixed){
		var box = $(this);
		if (! box[0]){
			return this;
		}
		if(isfixed == null || typeof isfixed != 'boolean'){
			isfixed = true;
		}
		var pageSizeArr = [
			document.documentElement.scrollWidth,
			document.documentElement.scrollHeight,
			document.documentElement.clientWidth,
			document.documentElement.clientHeight
		];
		var isIE6 = $.browser.msie && $.browser.version == '6.0';
		$('.close', box).bind('click', function (e){
			e.preventDefault();
			if ($.browser.msie){
				$('#dialogBackground').hide();
				$('#dialogBackgroundiframe').hide();
				box.hide();
			} else {
				$('#dialogBackground').fadeOut(200);
				$('#dialogBackgroundiframe').fadeOut(200);
				box.fadeOut(200);
			}
			$(this).unbind('click');
			$(window).unbind('scroll.dialogScroll');
		});
		
		var createDialog = function (){
			//如果是IE6 则创建iframe
			if (isIE6){
				var backgroundiframe = $('<iframe>',{
						id: 'dialogBackgroundiframe',
						frameborder: '0'
					}).css({
					position: 'absolute',
					background: '#000',
					zIndex: 990,
					//border: '1px solid red',
					top: 0,
					left: 0,
					width: pageSizeArr[2] > pageSizeArr[0] ? pageSizeArr[2] : pageSizeArr[0],
					height: pageSizeArr[3] > pageSizeArr[1] ? pageSizeArr[3] : pageSizeArr[1],
					zoom:1,
					display: 'none'
				});
				
				if ($.browser.msie){
					backgroundiframe.css('filter', 'Alpha(Opacity=60)');
				} else {
					backgroundiframe.css('opacity', '0.6');
				}
				backgroundiframe.appendTo('body');
				backgroundiframe.show();
			}
				
			var backgroundDiv = $('<div>',{
					id: 'dialogBackground'
				}).css({
				position: 'absolute',
				background: '#000',
				zIndex: 991,
				top: 0,
				left: 0,
				width: pageSizeArr[2] > pageSizeArr[0] ? pageSizeArr[2] : pageSizeArr[0],
				height: pageSizeArr[3] > pageSizeArr[1] ? pageSizeArr[3] : pageSizeArr[1],
				zoom:1,
				display: 'none'
			});
			if ($.browser.msie){
				backgroundDiv.css('filter', 'Alpha(Opacity=60)');
			} else {
				backgroundDiv.css('opacity', '0.6');
			}
			backgroundDiv.appendTo('body');
			backgroundDiv.show();
		};
		
		var dialogshow = function (){
			if ($('#dialogBackground')[0]) {
				$('#dialogBackground').show();
				$('#dialogBackgroundiframe').show();
			} else {
				createDialog();
			}
			if (isIE6){
				box.css({
					position: 'absolute',
					zIndex: 999,
					top: document.documentElement.scrollTop + (document.documentElement.clientHeight - box.height()) / 2,
					left: document.documentElement.scrollLeft + (document.documentElement.clientWidth - box.width()) / 2
				});
			} else {
				box.css({
					position: (isfixed ? 'fixed' : 'absolute'),
					zIndex: 999,
					left: '50%',
					marginLeft: 0 - box.width() / 2
				});
				if (isfixed){
					box.css({
						top: '50%',
						marginTop: 0 - box.height() / 2
					});
				}
			}
			box.show();
		};
		
		if (isIE6 && isfixed){
			$(window).bind('scroll.dialogScroll', function (){
				box.css({
					top: document.documentElement.scrollTop + (document.documentElement.clientHeight - box.height()) / 2,
					left: document.documentElement.scrollLeft + (document.documentElement.clientWidth - box.width()) / 2
				});
			});
		}
		
		dialogshow();
		return this;
	};
})(jQuery);