JQuery Mobile is a version of HTML5 UI development that has been optimized to adjust the appearance of a web browser on several devices like smartphones, tablets, PC and others.

Reasons for Using JQuery Mobile :

Every mobile device has an operating system that is not the same, for example, Android, iOS, Windows Phone and others. All of these devices have different browser views. So you don't need to develop on several different devices, then jQuery Mobile comes with feature a cross-platform website / app that can be applied once and can be used in several OS with basic HTML, CSS, and JavaScript that standard.