导航条兼容问题

.nav_left {

width:10px;

background:url(../../../%E6%9C%AA%E5%91%BD%E5%90%8D%E7%AB%99%E7%82%B9%202/images/nav_left.jpg)no-repeat;

}

.nav_mid {

width:980px;

background:url(../../../%E6%9C%AA%E5%91%BD%E5%90%8D%E7%AB%99%E7%82%B9%202/images/nav_bg.jpg) repeat-x;

line-height: 40px;

}

.nav_right {

width:10px;

background:url(../../../%E6%9C%AA%E5%91%BD%E5%90%8D%E7%AB%99%E7%82%B9%202/images/nav_right.jpg) no-repeat;

}

为什么在IE下导航背景显示不出来