// 定义最小宽度
function move(x,y){
	$(this).css("background-position",x+"px " +y +"px");
}
$.fn.minWidth = function(width){
$(this).each(function(){
	var $this = $(this);
	var resize = function(){
		if($(window).width() < width){
			$this.width(width);
		} else {
			$this.width("100%");
		}
	};
	resize();
	$(window).resize(resize);
		});
	};