The prefixes like -moz-, -webkit-, and -o- are specifically for NOT contaminating the DOM with objects that are not standard compliant. These prefixes mark prop

The prefixes like -moz-, -webkit-, and -o- are specifically for NOT contaminating the DOM with objects that are not standard compliant. These prefixes mark proposed features that are still in discussion for W3C standardization and they are introduced so they can be tested in practice. Once they are standardized, the prefixes can be dropped. That is exactly how it should be. The -moz- prefix was first, and -webkit- came later.