History of String.prototype.search()

Standardize "Return value" section as per Bug 1287421

Bug 1108382 - Remove non-standard flag argument from String.prototype.{search,match,replace}

Bug 1245801 - Disable non-standard flag argument of String.prototype.{search,match,replace} in non-release build.

Simple grammar correction.

Made it more clear the difference between search and test.

add ES draft

The "return value" has its specific section. It's not a part of a description as a standard paragraph