function Font(family, size) { var container = document.createElement('div'), img = document.createElement('img'), span = document.createElement('span'), sampleText = 'Hidden Text', baseline, middle; container.style.visibility = "hidden"; container.style.fontFamily = family; container.style.fontSize = size; container.style.margin = 0; container.style.padding = 0; document.body.appendChild(container); img.src = smallImage(); img.width = 1; img.height = 1; img.style.margin = 0; img.style.padding = 0; img.style.verticalAlign = "baseline"; span.style.fontFamily = family; span.style.fontSize = size; span.style.margin = 0; span.style.padding = 0; span.appendChild(document.createTextNode(sampleText)); container.appendChild(span); container.appendChild(img); baseline = (img.offsetTop - span.offsetTop) + 1; container.removeChild(span); container.appendChild(document.createTextNode(sampleText)); container.style.lineHeight = "normal"; img.style.verticalAlign = "super"; middle = (img.offsetTop-container.offsetTop) + 1; document.body.removeChild(container); this.baseline = baseline; this.lineWidth = 1; this.middle = middle; }