[CSS] IE8 顯示背景圖的icon的解決方法

遇到IE8的背景圖跑不出來的問題，另外ie8也看不懂 background-position 與 background-size

「background-size」是 CSS3 才有的進階語法，ie9後才有支援
.nav-icon-devicemgmt{
    background: url('../images/icons/nav-icon-devicemgmt.png') no-repeat left  ;
}

/*IE8可跑*/
.nav-icon-devicemgmt{  
    background-size: 32px 32px;
    background-image:url('../images/icons/nav-icon-devicemgmt.png') ;
    background-repeat:  no-repeat;
    background-position:  left ;
    background-position-x: 5px;
}