css遮罩层及遮罩层gif图片居中

遮罩层css代码：

.xy-backdrop{    display: none;    position: fixed;    z-index: 998;    top: 0;    right: 0;    bottom: 0;    left: 0;    background-color: rgba(0,0,0,.3);}

图片居中：

.xy-backdrop img{position: absolute;top: 50%;left: 50%;transform: translate(-50%,-50%);-ms-transform: translate(-50%,-50%);-o-transform: translate(-50%,-50%);-moz-transform: translate(-50%,-50%);-webkit-transform: translate(-50%,-50%);-khtml-transform: translate(-50%,-50%);}

使用如下：

<div class="xy-backdrop" onclick="showFlashDialog()"><img src="../images/phone/xy-icon/load3.gif"></div>

js代码：

function showFlashDialog(){$("div.yx-dialog-flash").css("display","block");$("div.xy-backdrop").css("display","block");}function hiddenFlashDialog(){$("div.yx-dialog-flash").css("display","none");$("div.xy-backdrop").css("display","");}