Stacked icons with one css class

Question

In new FontAwesome 4.0.0 there is css styles for stacked items.

<span class="fa-stack">
  <i class="fa fa-square-o fa-stack-2x"></i>
  <i class="fa fa-twitter fa-stack-1x"></i>
</span>

.fa-stack {
  position: relative;
  display: inline-block;
  width: 2em;
  height: 2em;
  line-height: 2em;
  vertical-align: middle;
}

.fa-stack-1x,
.fa-stack-2x {
  position: absolute;
  width: 100%;
  text-align: center;
 }
.fa-stack-1x {
  line-height: inherit;
}
.fa-stack-2x {
  font-size: 2em;
}

.fa-square-o:before {
  content: "\f096";
}

I want to do it only without using nested span and i, just only with some css-classes

.myclass1 { ... }
.myclass2 { ... }
<span class=".... myclass2" />

What is the simplest method to achieve the same result (using fa content classes ?)

Update: or is something like the following possible ?

 .myclass1:before { content:     '<span class="fa-stack">
  <i class="fa fa-square-o fa-stack-2x"></i>
  <i class="fa fa-twitter fa-stack-1x"></i>
</span>' }

     <span class=".... myclass1" />

Answer 1

(edited)

This is not possible with fa-* classes, because there is no possibility to determine the order of stacked icons: in CSS class="foo bar" is the same as class="bar foo"

On the other side, you can define your own class and style it to achieve one chosen stacked icon - i.e you'll need one custom class per every pair (e.g fa-times stacked on fa-square).

In order to achieve this, use :before and :after selectors (and absolute positioning - little demo).

It also seems (tested using background property) that :after element is on top of :before if you use absolute positioning. In case that's not true, you cvan always use z-index to order those two elements manually.

Answer 2

About your update, if something like the following possible ?

.myclass1:before { 
   content:'<span class="fa-stack">
      <i class="fa fa-square-o fa-stack-2x"></i>
      <i class="fa fa-twitter fa-stack-1x"></i>
    </span>' 
}

<span class=".... myclass1" />

It's not, as it is explained there : CSS content property: is it possible to insert HTML instead of Text?

If you want to keep control of the two stacked icon in a single HTML tag you can get it with something like that.

div{
  display:flex;
  justify-content: center;
  position:relative;
}

i:before {
    content: attr(icon-before); // "\f099";
    position: absolute; 
    font-size: 1.5em;
    margin:0.1em;
}

i:after {
    content: attr(icon-after); // "\f096";
    position: absolute; 
    font-size: 2.1em;
}

<link href="http://netdna.bootstrapcdn.com/font-awesome/4.0.0/css/font-awesome.css" rel="stylesheet"/>
<!--https://stackoverflow.com/questions/22600464/html-special-characters-in-css-content-using-attr-->

<div><i class="fa" icon-before="&#xf099" icon-after="&#xf096"></i></div>