Css WRITING PRINCIPLES

1.css selector the compiling method of css selector determines the number of matches that must be executed by the browser. Some Types of css selector will cause the browser to try more matches, therefore, the overhead is higher than the simple selector. This type of identifier is simple and efficient. It is used to match unique elements on a page. # Id {} class selector. className {} type selector tagName {} adjacent sibling selector H1 + # toc {} subselector # toc> li {} descendant selector # toc A {} wildcard selector * {} attribute selector [href = "# index"] {} pseudo class and pseudo element: hover {} key to efficient css selector 1) rightmost priority in fact, css selector matches from right to left. 2) Write efficient css delimiters to avoid using wildcard rules: only ID and class delimiters are used instead of ID delimiters: do not apply any other delimiters to the left of the ID selector. Do not use a specific tag to restrict class delimiters. Instead, expand the class names based on the actual situation. The more specific the rule, the better. Avoid using the descendant selector. Avoid using tags as subselector. Rely on inheritance to carefully check the usage of subselector.