modernizr/feature-detects/unicode.js

Modernizr is a JavaScript library that detects HTML5 and CSS3 features in the user’s browser.

/*!
{
  "name": "Unicode characters",
  "property": "unicode",
  "tags": ["encoding"],
  "warnings": [
    "positive Unicode support doesn't mean you can use it inside <title>, this seams more related to OS & Language packs"
  ]
}
!*/
/* DOC

Detects if unicode characters are supported in the current document.

*/
define(['Modernizr', 'createElement', 'testStyles'], function( Modernizr, createElement, testStyles ) {
  /**
   * Unicode special character support
   *
   * Detection is made by testing missing glyph box rendering against star character
   * If widths are the same, this "probably" means the browser didn't support the star character and rendered a glyph box instead
   * Just need to ensure the font characters have different widths
   */
  Modernizr.addTest('unicode', function() {
    var bool;
    var missingGlyph = createElement('span');
    var star = document.createElement('span');

    testStyles('#modernizr{font-family:Arial,sans;font-size:300em;}', function( node ) {

      missingGlyph.innerHTML = '&#5987';
      star.innerHTML = '&#9734';

      node.appendChild(missingGlyph);
      node.appendChild(star);

      bool = 'offsetWidth' in missingGlyph && missingGlyph.offsetWidth !== star.offsetWidth;
    });

    return bool;

  });
});