The term “empty element” comes from SGML, on which HTML standards prior to HTML5 were based, and where the EMPTY keyword is used to represent elements with an empty content model. Here’s what the HTML 4 spec says: The allowed content for an element is called its content model. Element types that are designed to … Read more
Buksy’s answer is correct but in my opinion it does not answer the original question, namely: “What can service workers do that web workers cannot? Or vice versa?” There are fundamental differences in their lifecycle and the number of instances per origin you can have. In short: | Web Workers | Service Workers | |————–|————–|——————| … Read more
Dublin Core proposes the rightsHolder term (an extension to the <meta> name attribute), which validates using the W3C HTML5 validator: <meta name=”dcterms.rightsHolder” content=”Your Copyright-Holder Organization”> This is defined as A person or organization owning or managing rights over the resource. Additional terms: For a statement about property rights, we can use the regular rights term: … Read more
W3C has a great post on the subject of CSS units. In particular: cm: Not recommended for screen / recommended for print The so-called absolute units (cm, mm, in, pt and pc) mean the same in CSS as everywhere else. A length expressed in any of these will appear as exactly that size (within the … Read more
To me, linebreaks should only be used inside paragraphs to indicate a new line. Adding line-breaks between paragraphs was used back in the day, when HTML looked like Chop Suey and the semantics of the HTML document looked like someone from preschool used Dreamweaver. I personally rely on margins and padding for content separation, if … Read more
The recommended way is through DOM manipulation, but it can be quite verbose. For example: // <p>Hello, <b>World</b>!</p> var para = document.createElement(‘p’); para.appendChild(document.createTextNode(‘Hello, ‘)); // <b> var b = document.createElement(‘b’); b.appendChild(document.createTextNode(‘World’); para.appendChild(b); para.appendChild(document.createTextNode(‘!’)); // Do something with the para element, add it to the document, etc. EDIT In response to your edit, in order to … Read more
You can use Promise: var lat,lon; var promise1 = new Promise(function(resolve, reject) { navigator.geolocation.getCurrentPosition(function(pos){ lat = pos.coords.latitude lon = pos.coords.longitude resolve({lat,lon}); }) }) promise1.then(function(value) { console.log(value.lat,value.lon) });
Check that your page isn’t in Quirks mode or Compatibility mode. You can use the F12 dev tools to confirm this. Press F12 and look in the top-right corner of the resulting window. If you see “Compatibility” or “Quirks” in the mode description, then you’ve found the problem. Quirks mode: this is usually triggered by … Read more
The W3C publishes many drafts and proposals which are then discussed within the community at large. If a draft makes it to the stage where it’s generally considered useful, browser vendors will/may start implementing it. The draft then typically advances to a “recommendation” stage, meaning the W3C officially recommends that browsers implement the technology as … Read more
Your understanding of the W3C references is correct, but your understanding of the red box is not. The red box does not depict the em-square. Its height is the sum of the ascent and descent from the metrics.