Permission to use getUserMedia(), unless the top-level context expressly
Only a window's top-level document context for a valid origin can even request In addition, user permission is always required to access the user's audio and video Using HTTPS or the file:/// URL scheme, or a page loaded from A secure context is, in short, a page loaded GetUserMedia() is a powerful feature which can only be used in secure contexts in insecureĬontexts, diaDevices is undefined, preventingĪccess to getUserMedia(). Specification lays out a wide array of privacy and security requirements that browsers One setback I'm thinking of is responsive capability.As an API that may involve significant privacy concerns, getUserMedia()'s So the concern about premature optimization expressed by some commenters and shared by me is probably warranted. The article is referenced in the note at the top of the outdated 2000 article Writing efficient CSS by David Hyatt. A good source about modern-day CSS optimization, BTW. Quote via CSS Selector Performance has changed! (For the better) by Nicole Sullivan. My view is that authors should not need to worry about optimizing selectors (and from what I see, they generally don’t), that should be the job of the engine. This is actually in accordance with what Antti Koivisto, a contributor to WebKit core, said in 2011, having spent some time optimizing its CSS selector matching:
Html optimizer for browser or resolution code#
Otherwise, writing semantically correct code is their best bet. due to being unable to solve the halting problem). Programmers can take care only of the things that the compiler is unable to deduce (e.g. The compiler is responsible for optimization, because it knows about its implementation details and is able to tell, which fits its needs best. I used this imageīrowsers should be doing any such optimization internally, as they “compile” the CSS. The code for generating image1.html, image2.html and image3.html can be found here You can use ANY PNG image.
Than read the pixel value of that PNG and create the same picture using CSS and DIV-elements. Should you limit the amount of classess per DOM object? should you prefer a "single attribute containing class" over adding it to an ID? What CSS code is hypothetically the most optimized? (for modern browsers) But as you can imagion, when more DOM objects exist, and more overlap of attributes exist, you could theoretically end up with one DOM object with 1 ID and 10'ths of classes! Now these are three simple examples of CSS code. But notice that A, B and C end up with one ID, and 4 classes that contain only one attribute! (see image3.html) The file would be even smaller (most of the time) and as it turns out the rendering goes quicker as well. (image1.html, see file generating script below) However, the file would be very large, the attributes are not shared and a simple test proofs that this is rather slow to render. There are multiple ways you can generate the css code for this web: Whereas all numbers represent a unique attributes. The question is: What CSS code is hypothetically the most optimized? (for modern browsers)Ī, B, C and D are DOM-objects (lets say DIV-elements) and the numbers 1-17 represent attributes (like color, background, width, height, etc) However, computers can take into account way more in almost no time and are thus better in optimizing. As a web developer, you can only go to a certain amount of effort to optimize your CSS code.
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