.caption {
text-align: justify;
text-align-last: center;
}The text-align-last property describes how the last line of a block or a line right before a forced line break is aligned when ‘text-align’ is ‘justify’, which means you gain full control over the alignment of the last line of a block.
As seen in the example above it allows you to have the caption’s alignment set to justify;, except for the last line (normally it would end up left aligned). Available in Webkit (under a flag).
Improving your site’s visual details: CSS3 text-align-last →