In the past, if you wanted to develop IOS or Android apps, you needed to know different programming languages or frameworks. For instance, for IOS app development, you need to know Swift, which is written in Objective-C and is used to develop IOS apps or for Android app, and Java. More and more time is needed to develop IOS or Android apps. Fortunately, big companies like Facebook, Microsoft and Adobe Systems have recently released open-source cross-platform frameworks where you can develop IOS and Android apps. I am going to give more information about some of the latest technologies in app development.

PhoneGap:
PhoneGap is a mobile application development framework originally created by Nitobi (later, Adobe System acquired Notibi in 2011).Adobe Systems renamed Apache Cordova and made it open source under Apache 2.0 License. PhoneGap is written in C#, C++,CSS, JavaScript and Objective-C. You can develop IOS and Android app through HTML,CSS and Javascript like the way you develop web applications. To anyone who is familiar with Web development, it will be much easier for them to work on PhoneGap as its core is the same. Even though applications are developed using HTML, CSS and Javascript, the final product of PhoneGap is binary application archive that is compatible with Apple IOS or Google Android applications.

For IOS applications, the output is an IPA file (IOS Application Archive), for Android Applications an APK file (Android package).
PhoneGap also provides an application programming interface (API) that enables a developer to access native operating system functionalities through Javascript.

Flutter:
Flutter is an open-source mobile application framework created by Google and you can develop cross-platform mobile applications. Flutter’s engine was written on C++ which provides low-level rendering support using Google’s Skia graphics library. It also interfaces with native operating functionalities. For UI, Flutter uses Widgets that are used to create graphics, texts, shapes, and animations. The fact is that Flutter uses reactive view but Flutter does not use JavaScript to bridge between OEM Widgets and native operating system functionalities like camera, memory, etc. It does so by compiled programming language called Dart. Widgets are the elements that affect and control the view and interface to an app. In other words, widgets are one the most important parts of Flutter. Not using Javascript bridge makes an app run faster and smoothly.As you can see, big companies are constantly working on making new technologies in mobile development. The tip of the day is to keep an eye on new technologies in mobile development and keep exploring!

Reference:
https://phonegap.com/blog/2012/05/02/phonegap-explained-visually/
https://hackernoon.com/whats-revolutionary-about-flutter-946915b09514
https://en.wikipedia.org/wiki/Flutter_(software)