怎样让你的背景图片不变动

body{ margin:0; padding:0;} 
#con{ 
position:absolute; 
top:0; 
left:0; 
height:100%; 
width:100%; 
background-image:url("maskimg/star.jpg"); 
background-position: center 0; 
background-repeat: no-repeat; 
background-attachment:fixed; 
background-size: cover; 
-webkit-background-size: cover;/* 兼容Webkit内核浏览器如Chrome和Safari */ 
-o-background-size: cover;/* 兼容Opera */ 
zoom: 1; 
}