iframe{
    -webkit-transform: translate(-50%,-50%);
    -moz-transform: translate(-50%,-50%);
    transform: translate(-50%, -50%);
    top: 50%;
    left: 50%;
    position: fixed;
    display: none;
    position: fixed;
    z-index: 99;
    width: 300px;
    height: 200px;
    background-color:silver;
    }