(function($) {
	//斑马线
	$.fn.zebra = function(color1, color2) {
		$(this).each(function(x) {
			if(x % 2 == 0) {
				$(this).css('background-color', color1);
			}
			else {
				$(this).css('background-color', color2);
			}
		});
	};

	//鼠标hover效果
	$.fn.lighten = function(color1, color2) {
		var t_color;
		$(this).hover(function(x) {
			 t_color = $(this).css('background-color');
			$(this).css('background-color', color1);
		},
		function() {
			if(color2) {
				$(this).css('background-color', color2);
			}
			else {
				$(this).css('background-color', t_color);
			}
		});
	};


	//附上阴影透明背影
	$.fn.shadow = function(class_name) {
		$(this).before('<div style="z-index:1;-moz-opacity:0.5;filter:alpha(opacity=50);position:absolute;background:#000;width:100%;height:100%;" class="' +class_name+ '">&nbsp;</div>');
	}

	$.fn.align = function(align) {
		switch(align) {
			case 'center':
				var left = (screen.width - this.width())/2;
				var top = (screen.height - this.height())/4+this.height()/2;
				this.css({'position':'absolute', 'left':left, 'top':top});
				break;
			case 'right':
				this.css({'position':'absolute', 'right':0});
				break;
		}
	}

	//拖拽
	$.fn.drag = function() {
		var _this = this;

//		var left = (screen.width - _this.width())/2;
//		var top = (screen.height - _this.height())/4+_this.height()/2;

//		_this.css({'z-index':12,'position':'absolute', 'left':left, 'top':top});
		_this.css({'z-index':12,'position':'absolute'});

		var dragObject = null;  //拖拽对象
		var mouseOffset = {}; //对象位置

		//捕获鼠标X,Y坐标
		function mouseCoords(ev) {	
			if(ev.pageX || ev.pageY) {
				return {x:ev.pageX, y:ev.pageY};
			}
			return {
				x:ev.clientX + document.body.scrollLeft - document.body.clientLeft,
				y:ev.clientY + document.body.scrollTop  - document.body.clientTop
			};
		}

		//捕获鼠标位置
		function getMouseOffset(target, ev) {		
			ev = ev || window.event;
			var docPos = getPosition(target);
			var mousePos  = mouseCoords(ev);
			return {
				x:mousePos.x - docPos.x, 
				y:mousePos.y - docPos.y
			}; 
		} 
		
		//捕获对象位置
		function getPosition(e) {
			var left = _this.offset().left;
			var top = _this.offset().top;
			return {x:left, y:top};
		}

		//鼠标移动
		document.onmousemove = function(ev) {
			ev = ev || window.event;
			var mousePos = mouseCoords(ev);
//			_this.html('鼠标x坐标：' + (mousePos.x-mouseOffset.x)+ '鼠标y坐标：' + (mousePos.y-mouseOffset.y));
			_this.html('l：' + _this.offset().left+ 't：' + _this.offset().top);

			

			if(dragObject) {
				var l = mousePos.x - mouseOffset.x;
				var t = mousePos.y - mouseOffset.y;
				$(dragObject).css({'left':l, 'top':t});
			}
			return false;
		};

		//按下鼠标
		_this.mousedown(function(ev) {
			dragObject  = this;
			mouseOffset = getMouseOffset(this, ev);
			return false;
		})

		//放开鼠标
		_this.mouseup(function() {

			dragObject = null; 
		})
	}

})(jQuery)