AJAX is an acronym for Asynchronous JavaScript And XML, used for creating asynchronous web applications. AJAX is popular for “Partial-Page Update” capability. AJAX provides the method for asynchronous data exchange between client and server to avoid full page reloads. AJAX allows high level of interactivity and processing. AJAX is used for creating feature-rich dynamic web applications handling a number of events in one interface. AJAX helps in creating more responsive web applications. AJAX uses more than one technology for developing potential applications.
Bootstrap is a strong mobile-first CSS framework developed by Mark Otto and Jacob Thornton at Twitter for quicker web development. Bootstrap is capable to produce responsive websites effortlessly.
Reasons to choose the Bootstrap:
Simpler to understand
Enhanced HTML elements
Substantial grid system
Nice list of components
Collection of Javascript plugins
Documentation