CSS browser compatibility ---- Hack and css compatibility ---- hack

CSS browser compatibility ---- Hack and css compatibility ---- hack
CSS Hack has three forms: CSS internal Hack, selector Hack, and HTML header reference (if IE) Hack. CSS Hack is mainly used for IE browsers.
Internal Hack: for example, IE6 can recognize underscores (_) and star numbers (*). IE7 can recognize asterisks (*) but cannot recognize underscores "_", firefox does not know either of them. And so on.
Selector Hack: for example, IE6 can recognize * html. class {}, IE7 can recognize * + html. class {}, or *: first-child + html. class {}. And so on.
HTML header reference (if IE) Hack: For all IE: <! -- [If IE]> <! -- Your code --> <! [Endif] --> for IE6 and earlier versions: <! -- [If lt IE 7]> <! -- Your code --> <! [Endif] --> this type of Hack not only takes effect for CSS, but also for all code written in the judgment statement.
The writing order is generally to write the CSS of the browser with strong recognition ability in front. Browser priority: FF <IE7 <IE6, CSS hack is generally written in FF IE7 IE6.