CSS样式中,background-image 背景图片居中显示并且在不同屏幕分辨率下始终居中

body {  

margin-top:0px;

margin-right:0px;  

margin-bottom:0px;  

margin-left:0px;  

background-color:#CCDAF7;  

background-image:url(../images/loadbg.jpg);  

background-repeat:no-repeat;  

background-position:top;  

background-attachment:fixed;

}