ajax vs rest

JavaScript
In Ajax, the request are sent to the
server by using XMLHttpRequest objects.
The response is used by the JavaScript 
code to dynamically alter the current page
Ajax is a set of technology; it is a technique
of dynamically updating parts of UI
without having to reload the page
Ajax eliminates the interaction between
the customer and server asynchronously.

Rest
REST have a URL structure and a request/response
pattern the revolve around the use of resources
REST is a type of software architecture and
a method for users to request data or 
information from servers
REST requires the interaction between 
the customer and server
Source

Also in JavaScript: