Vertically and Horizontally Center Image inside a Div, if you don't know Image's Size?

Question

If I have a fixed sized container div, and an unknown sized image, how do I horizontally and vertically center it?

• using pure css
• using JQuery if css

Answer 1

If setting the image as a background image and centering it that way isn't an option, the jQuery to adapt the answer you linked for static images would go:

$(".fixed-div img.variable").each(function(){
  //get height and width (unitless) and divide by 2
  var hWide = ($(this).width())/2; //half the image's width
  var hTall = ($(this).height())/2; //half the image's height, etc.

  // attach negative and pixel for CSS rule
  hWide = '-' + hWide + 'px';
  hTall = '-' + hTall + 'px';

  $(this).addClass("js-fix").css({
    "margin-left" : hWide,
    "margin-top" : hTall
  });
});

assuming a CSS class defined as

.variable.js-fix {
  position:absolute;
  top:50%;
  left:50%;
}

with the fixed-width div having a height and position:relative declared.

[important js edit: switched '.style()' to '.css()']