4 Answers. CSS selectors are generally case-insensitive; this includes class and ID selectors. But HTML class names are case-sensitive (see the attribute definition), and that’s causing a mismatch in your second example. This has not changed in HTML5.
Are CSS selectors bad?
Having a very specific selector will not amount to bad performance, but if there are a lot of declarations applicable for an element, then the performance will take a hit. The only concern otherwise is that it increases the no. of bytes to be downloaded for loading the stylesheet.
Should CSS classes be capitalized?
Using Title CSS, you’d do the following: For any global CSS class, use a capitalized name (title case). For any modifier or descendant class, use a lowercase letter for the beginning of th name. This means with Title CSS you capitalize any class name that will get referenced in the stylesheet without a parent class.
Does CSS selector performance matter?
The short answer is; probably not. The longer answer is; it depends on the site you’re building. If you’re working on your next portfolio then go for clean code over CSS selector performance, because you really aren’t likely to notice it.
Which CSS selector is fastest?
Even in such an extreme case, with 50000 elements to match, and using some really insane selectors like the last one, we find that the slowest one is ~20ms, while the fastest is the simple class at ~3.5ms. Not really that much of a difference.
How do I force CSS override?
How to override !important. A) Add another CSS rule with !important , and either give the selector a higher specificity (adding a tag, id or class to the selector), or add a CSS rule with the same selector at a later point than the existing one. This works because in a specificity tie, the last rule defined wins.
How many lines of CSS is too much?
If it is a small blog and you need, say, 3000 lines of CSS, that is probably too much. If it is an online store with multiple sections and a complicated layout, it might not be enough.
Should CSS be camel case?
Because CSS is case-insensitive, it’s better to write all names in lower-case (or upper-case); avoid camel-case or pascal-case as they can lead to ambiguous names.
What is position attribute in CSS?
The position CSS property sets how an element is positioned in a document. The top , right , bottom , and left properties determine the final location of positioned elements.
What is the most efficient way to use CSS?
7 Important Tips for Writing Better CSS
- DRY. DRY stands for “Don’t Repeat Yourself”. …
- Naming. Naming CSS selectors is another important point for writing better CSS. …
- Don’t Use Inline-Styles. …
- Avoid the ! …
- Use a Preprocessor. …
- Use Shorthands. …
- Add Comments When Necessary.
How can I make my CSS more efficient?
20 Tips for Optimizing CSS Performance
- Learn to Use Analysis Tools. You can’t address performance problems unless you know where the faults lie. …
- Make Big Wins First. …
- Replace Images with CSS Effects. …
- Remove Unnecessary Fonts. …
- Avoid @import. …
- Concatenate and Minify. …
- Use Modern Layout Techniques. …
- Reduce CSS Code.
How do you optimize CSS selectors?
In David’s article he offered some guidelines for writing efficient css selectors, which I’ll present below.
- Avoid Universal Rules.
- Don’t qualify ID Rules with tag names or classes.
- Don’t qualify Class Rules with tag names.
- Use the most specific category possible.
- Avoid the descendant selector.
Which is faster XPath or CSS?
Advantages of Using CSS Selector
It’s faster than XPath. It’s much easier to learn and implement. You have a high chance of finding your elements. It’s compatible with most browsers to date.
Which is most faster XPath or CSS?
CSS is faster than XPath. … It is very useful when we want to test our application on multiple browsers because CSS engine are consistent in all browsers. CSS is best for IE as XPath does not work in IE always.
Which is faster XPath or CSS selector?
CSS Selectors tend to perform better, faster and more reliable than XPath in most browsers.