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Here you can Sed posuere consectetur est at lobortis. Donec ullamcorper nulla non metus auctor fringilla. Maecenas sed diam eget risus varius blandit sit amet non magna. Donec id elit non mi porta gravida at eget metus. Praesent commodo cursus magna, vel scelerisque nisl consectetur et.

            
              <svg style="display:none;">
  <defs>
    <symbol id="icon-heart" viewBox="0 0 32 32" fill="currentColor">
      <path d="M0 10 C0 6, 3 2, 8 2 C12 2, 15 5, 16 6 C17 5, 20 2, 24 2 C30 2, 32 6, 32 10 C32 18, 18 29, 16 30 C14 29, 0 18, 0 10  "></path>
    </symbol>
    <symbol id="icon-close" viewBox="0 0 32 32" fill="currentColor">
      <path d="M4 8 L8 4 L16 12 L24 4 L28 8 L20 16 L28 24 L24 28 L16 20 L8 28 L4 24 L12 16 z "></path>
    </symbol>
    <symbol id="icon-hamburger" viewBox="0 0 32 32" fill="currentColor">
      <path d="M3 8 A3 3 0 0 0 9 8 A3 3 0 0 0 3 8 M12 6 L28 6 L28 10 L12 10z M3 16 A3 3 0 0 0 9 16 A3 3 0 0 0 3 16 M12 14 L28 14 L28 18 L12 18z M3 24 A3 3 0 0 0 9 24 A3 3 0 0 0 3 24 M12 22 L28 22 L28 26 L12 26z "></path>
    </symbol>
  </defs>
</svg>

<h1>Progressive SVGs</h1>

<div class="buttons" data-codeblock>
  
  <button aria-label="Like">
    <span class="inline-svg" data-xlink="#icon-heart">♥</span>
  </button>

  <button aria-label="Close">
    <span class="inline-svg" data-xlink="#icon-close">Close</span>
  </button>

  <button aria-label="Menu">
    <span class="inline-svg" data-xlink="#icon-hamburger" >&#x2261;</span>
  </button>

  <p><a href="#">Do you <span class="inline-svg" data-xlink="#icon-heart" title="like">♥</span> me?</a></p>

  <button aria-label="Like">
    <span class="inline-svg" data-xlink="#icon-heart">♥</span> Like
  </button>

</div>


## Working theory:

Most inline SVGs don't need fallbacks, they're icon candy paired with assistive text and/or they are decorative (like icon-fonts). This aims at **progressively enhancing critical fallbacks** when absolutely necessary. So, we take a span, with a little extra meta and replace it with an SVG `<use>` element when it appears enhanceable.

How it looks in IE8

![](https://s3-us-west-2.amazonaws.com/s.cdpn.io/17/Screenshot_2014-12-17_17.19.56.png)


## Approach

I try to scope the Image Replacement (IR) to either text or unicode. There are 5 examples here:

1. A Like `button` with a Unicode "BLACK HEART SUIT" (♥) fallback. This heart is generally supported. Added an `aria-label` on the `button` to avoid screenreaders stumbling on wonky Unicode. VoiceOver failed on reading SVG `title` attributes in a `button`.
1. A Close button with "Close" as a text fallback. The Unicode "MULTIPLICATION SIGN" (×) character has decent support, but I wanted an example where you might fall back to text. Same ARIA approach as above.
1. A Hamburger button with fallback Unicode "IDENTICAL TO" (≡) character. Same ARIA approach, but very necessary due to the desired label being "Menu" which is very different than the character's meaning.
1. A link with a Unicode heart (♥) fallback. Adding a `title` attribute here actually improved the accessibility for both SVG and fallback span.
1. A Like button with "Like" text. This doesn't really even require a fallback.

## Rules

- Use similar Unicode when you can get away with it. 
  - See [Unify](https://unicode.johnholtripley.co.uk/all/support) by John Ripley to guage how well a character is supported across devices and screenreaders. 
- There's a bit of CSS you'll need to make sure old Windows uses 'Arial Unicode MS' as a fallback font with Unicode support.
- A lot of Zach Leatherman's [Bulletproof Icon Fonts](https://www.filamentgroup.com/lab/bulletproof_icon_fonts.html) applies here.
- Must be Accessible. Avoid wonky Unicode reading:
  - Add `aria-label` to parent `button` elements.
  - Use `title` attributes otherwise.
- If you used an external SVG (e.g., `some.svg#icon-hamburger`), you might be able to save legacy browsers the double download.

<small>SVGs from <a href="http://geomicons.com/">Geomicons</a></small>
            
          
!
            
              // General Style
html, body {
  background: #f0f0f0;
}

h1 {
  text-align: center;
}

body {
  font-family: sans-serif;
  padding: 5%;
  line-height: 1.6em;
}

img {
  max-width: 100%;
  height: auto;
}

.buttons {
  text-align: center;
}

pre {
  background: #fff;
  padding: 1em;
  max-height: 20em;
  overflow: auto;
  margin-bottom: 5%;
}

button {
  font-size: 1em;
  line-height: 1em;
}

// Inline SVG Code
// ====================================================
.inline-svg {
  display: inline-block;
}

span.inline-svg {
  // Unicode chars need a Unicode font on old browsers.
  font-family: 'Arial Unicode MS', Arial, sans-serif;
}

svg.inline-svg {
  // Tailor to suite your needs.
  width: 1em;
  height: 1em;
  vertical-align: text-top;
}
            
          
!
            
              (function(window, document){
  // Feature Test
  // TODO: Could be improved to detect INLINE only.
  var supportsSvg = function(){
    return document.implementation && document.implementation.hasFeature("http://www.w3.org/TR/SVG11/feature#Image", "1.1");
  };

  // Enhance!
  if(supportsSvg) {
    var inlineSvgs = document.querySelectorAll('span.inline-svg');

    for(i=0;i<inlineSvgs.length;i++) {
      var span = inlineSvgs[i];
      var svgns = "http://www.w3.org/2000/svg";
      var xlinkns = "http://www.w3.org/1999/xlink";
      var svg = document.createElementNS(svgns, "svg");
      var use = document.createElementNS(svgns, "use");
      
      // Prepare the <use> element
      use.setAttributeNS(xlinkns, 'xlink:href', span.getAttribute('data-xlink') );

      // Append it
      svg.appendChild(use);
      
      // Prepare the SVG
      svg.setAttribute('class', "inline-svg");

      // Set a title if necessary.
      if(span.getAttribute('title')) {
        svg.setAttribute('title', span.getAttribute('title'));      
      }

      // Inject the SVG
      span.parentNode.insertBefore(svg, span);
      
      // 6 Minute Abs™, for your DOM.
      span.remove();
    }
  }
})(window, document, undefined);
            
          
!
999px
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