Test for font fallback bug in Webkit

gistfile1.js

function detectWebkitFallbackBug() {
    var el = document.createElement('div'),
        style = document.createElement('style'),
        width = 0,
        hasBug = false;
                
    style.innerHTML = "@font-face{font-family:'__test__';src:url(data:application/x-font-woff;base64,) format('woff'),url(data:font/truetype;base64,) format('truetype');}";
    el.style.cssText = 'position:absolute;font-family:monospace;font-size:20px;';
    el.innerHTML = 'iii';

    document.body.appendChild(el);
    document.head.appendChild(style);
    width = el.clientWidth; 
    el.style.fontFamily = "'__test__', monospace, sans-serif"; 
    hasBug = width !== el.clientWidth;

    document.head.removeChild(style);
    document.body.removeChild(el);

    return hasBug;
}