How do I vertically align text in a div?

Question

I am trying to find the most effective way to align text with a div. I have tried a few things and none seem to work.

.testimonialText {
  position: absolute;
  left: 15px;
  top: 15px;
  width: 150px;
  height: 309px;
  vertical-align: middle;
  text-align: center;
  font-family: Georgia, "Times New Roman", Times, serif;
  font-style: italic;
  padding: 1em 0 1em 0;
}

<div class="testimonialText">
  Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor
  in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.
</div>

Answer 1

HTML

<div class="relative"><!--used as a container-->
    <!-- add content here to to make some height and width
    example:<img src="" alt=""> -->
    <div class="absolute">
        <div class="table">
            <div class="table-cell">
                Vertical contents goes here
            </div>
        </div>
    </div>
</div>

CSS

 .relative{
    position:relative;
 }
 .absolute{
    position:absolute;
    top:0;
    bottom:0;
    left:0;
    right:0;
    background:rgba(0,0,0,0.5);
 }
 .table{
    display:table;
    height:100%;
    width:100%;
    text-align:center;
    color:#fff;
 }
 .table-cell{
    display:table-cell;
    vertical-align:middle;
 }

Answer 2

There's a simpler way to vertically align the content without resorting to table/table-cell:

http://jsfiddle.net/bBW5w/1/

In it I have added an invisible (width=0) div that assumes the entire height of the container.

It seems to work in IE and FF (latest versions), didn't check with other browsers

  <div class="t">
     <div>
         everything is vertically centered in modern IE8+ and others.
     </div>
      <div></div>
   </div>

And of course the CSS:

.t, .t > div:first-child
{ 
    border:1px solid green;
}
.t
{
    height:400px;
}
.t > div 
{ 
    display:inline-block; 
    vertical-align:middle  
}
.t > div:last-child
{
    height:100%;    
}

Answer 3

Simple solution to an element of not knowing values

HTML

<div class="main">
    <div class="center">
        whatever
    </div>
</div>

CSS

.main {
    position: relative
}

.center {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    -webkit-transform: translate(-50%, -50%);
    -moz-transform: translate(-50%, -50%);
    -o-transform: translate(-50%, -50%);
}

Answer 4

According to Adam Tomat's answer there was prepared a jsfiddle example to align the text in div

<div class="cells-block">    
    text<br/>in the block   
</div>

by use display:flex in CSS

.cells-block {
    display: flex;
    flex-flow: column;
    align-items: center;       /* vertically   */
    justify-content: flex-end; /* horisontally */
    text-align: right;         /* addition: for text's lines */
}

with another example and few explanation in blog.