The JavaScript exception "return (or yield) not in function" occurs when a return or yield statement is called outside of a function.

The JavaScript warning "Date.prototype.toLocaleFormat is deprecated; consider using Intl.DateTimeFormat instead" occurs when the non-standard Date.prototype.toLocaleFormat() method is used. toLocaleFormat() is now removed and this warning message is obsolete.

The JavaScript warning about string generics occurs in Firefox versions prior to 68. String generics have been removed starting with Firefox 68, and these warning messages are obsolete.

# Contributors by commit history https://github.com/mdn/content/commits/main/files/en-us/web/javascript/reference/errors/bad_octal/index.md # Original Wiki contributors fscholz

# Contributors by commit history https://github.com/mdn/content/commits/main/files/en-us/web/javascript/reference/global_objects/intl/numberformat/numberformat/index.md # Original Wiki contributors...

# Contributors by commit history https://github.com/mdn/content/commits/main/files/en-us/web/javascript/reference/global_objects/intl/relativetimeformat/relativetimeformat/index.md # Original Wiki ...

The textInfo accessor property of Intl.Locale instances returns the ordering of characters indicated by either ltr (left-to-right) or by rtl (right-to-left) for this locale.

# Contributors by commit history https://github.com/mdn/content/commits/main/files/en-us/web/javascript/language_overview/index.md # Original Wiki contributors

# Contributors by commit history https://github.com/mdn/content/commits/main/files/en-us/web/javascript/guide/regular_expressions/unicode_property_escapes/index.md # Original Wiki contributors JNa0...

JavaScript is a prototype-based language — an object's behaviors are specified by its own properties and its prototype's properties. However, with the addition of classes, the creation of hierarchies of objects and the inheritance of properties and their values are much more in line with other object-oriented languages such as Java. In this section, we will demonstrate how objects can be created from classes.