Vertically aligning div with fixed div as a parent? - html

Question

I have a relatively div positioned on top of a fixed position div and I would like to vertically align this first div. Is there a way to do this? This is my current markup:
<div class="overlay">
<div id="dialogInvoice">
content
</div>
</div>
The CSS:
.overlay {
height: 100%;
width: 100%;
top: 0;
left: 0;
background-color: rgba(0,0,0,0.5);
position: fixed;
z-index: 10;
}
#dialogInvoice {
width: 390px;
height: 722px;
margin: 0 auto;
padding-top: 28px;
border-radius: 4px;
background: #ffffff;
position: relative;
}
Any suggestions on this? I did try the line-height method but this is apparently only working when using mere text.

Answer 1

If your element does not have a fixed width or height then you can't use the other solutions without using javascript to calculate the values.
Here is an alternative.
#dialogInvoice {
width: 390px;
height: 722px;
padding-top: 28px;
border-radius: 4px;
background: #ffffff;
position: absolute;
left:50%;
top:50%;
-webkit-transform: translate(-50%, -50%);
-moz-transform: translate(-50%, -50%);
transform: translate(-50%, -50%);
}

Answer 2

what you need to add to your css of #dialogInvoice is
top: 50%;
and change the margin to
margin: 361px auto;
(361 is 722 / 2)
it will first push your container half way down the page and then push it back up the required value, which is exactly half of its height (361px)
here is a jsfiddle for better understanding.

Answer 3

This CSS may do what you require:
.overlay {
height: 100%;
width: 100%;
top: 0;
left: 0;
background-color: rgba(0,0,0,0.5);
position: fixed;
z-index: 10;
}
#dialogInvoice {
margin: 0 auto;
padding-top: 28px;
border-radius: 4px;
background: #ffffff;
position: absolute;
top: 100px;
bottom:100px;
left:100px;
right:100px;
}