This page lists features of JavaScript that are still available but planned for removal. These features can still be used, but should be used with caution because they are expected to be removed entirely sometime in the future. The following properties are now properties of RegExp instances, no longer of the RegExp object. Octal escape sequences (\ followed by one, two, or three octal digits) are deprecated in string and regular expression literals. Non-standard String generic methods like String.prototype.slice(myStr, 0, 12), String.replace(MyStr, /\./g, "!"), etc. have been introduced in Firefox.