Detecting with Javascript whether a Browser supports Web Open Font Format (Woff) or not

Question

i have to detect with JS (jQuery) wether a browser supports Woff and then add a class to the body. Something like this:

    if(woffIsSupported){

    $('body').addClass('modern');

    }

is this somehow possible? Thank you for your answers.

Answer 1

There's a function on this post called isFontFaceSupported that checks for support based on browser features (the good way, i.e. not relying on the user agent string).

Copy that function and your code can become:

if(isFontFaceSupported()) {
  $('body').addClass('modern');
}

---

Here is the function from the post:

/*!
 * isFontFaceSupported - v0.9 - 12/19/2009
 * http://paulirish.com/2009/font-face-feature-detection/
 *
 * Copyright (c) 2009 Paul Irish
 * MIT license
 */

var isFontFaceSupported = (function(){


    var fontret,
        fontfaceCheckDelay = 100;

      // IE supports EOT and has had EOT support since IE 5.
      // This is a proprietary standard (ATOW) and thus this off-spec,
      // proprietary test for it is acceptable.
    if (!(!/*@cc_on@if(@_jscript_version>=5)!@end@*/0)) fontret = true;

    else {

    // Create variables for dedicated @font-face test
      var doc = document, docElement = doc.documentElement,
          st  = doc.createElement('style'),
          spn = doc.createElement('span'),
          wid, nwid, body = doc.body,
          callback, isCallbackCalled;

      // The following is a font, only containing the - character. Thanks Ethan Dunham.
      st.textContent = "@font-face{font-family:testfont;src:url(data:font/opentype;base64,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)}";
      doc.getElementsByTagName('head')[0].appendChild(st);


      spn.setAttribute('style','font:99px _,serif;position:absolute;visibility:hidden');

      if  (!body){
        body = docElement.appendChild(doc.createElement('fontface'));
      }

      // the data-uri'd font only has the - character
      spn.innerHTML = '-------';
      spn.id        = 'fonttest';

      body.appendChild(spn);
      wid = spn.offsetWidth;

      spn.style.font = '99px testfont,_,serif';

      // needed for the CSSFontFaceRule false positives (ff3, chrome, op9)
      fontret = wid !== spn.offsetWidth;

      var delayedCheck = function(){
        if (isCallbackCalled) return;
        fontret = wid !== spn.offsetWidth;
        callback && (isCallbackCalled = true) && callback(fontret);
      }

      addEventListener('load',delayedCheck,false);
      setTimeout(delayedCheck,fontfaceCheckDelay);
    }

    function ret(){  return fontret || wid !== spn.offsetWidth; };

    // allow for a callback
    ret.ready = function(fn){
      (isCallbackCalled || fontret) ? fn(fontret) : (callback = fn);
    }

    return ret;
})();