Question

I want to set an element whose position is absolute at center , means if element`s position are not absolute then we can do like :

            margin : 0 auto;

But how we can do the same thing for the element whose position is absolute.?

Answer 1

.target {
    position: absolute;
    left: 50%;   /* set left */
    width: 500px;  /* give width */
    margin-left: -250px; /* margin-left = width/2  */
}

and set its parent as position: relative

DEMO

A sample jQuery approach:

var width = $('.target').width();
$('.target').css({
    left: '50%',
    'margin-left': -(width / 2)
});

DEMO