Center a popup window on screen?

Question

How can we center a popup window opened via javascript window.open function on the center of screen variable to the currently selected screen resolution ?

Answer 1

.center{
    left: 50%;
    max-width: 350px;
    padding: 15px;
    text-align:center;
    position: relative;
    transform: translateX(-50%);
    -moz-transform: translateX(-50%);
    -webkit-transform: translateX(-50%);
    -ms-transform: translateX(-50%);
    -o-transform: translateX(-50%);   
}