As mentioned in Chapter 1, Introduction to Mobile Web ArcGIS Development, Bootstrap is a very popular framework for building web interfaces. It is made up of a combination of JavaScript, CSS, and fonts. It supports both CSS3 and HTML5. The framework considers both device limitations and user behavior. Key to the popularity of Bootstrap is its responsive system. This allows developers to build a single mobile web app that works well across a variety of devices with different screen sizes. This means a web app that looks good on the largest monitor down to the smallest smartphone.

The following screenshot illustrates the Responsive design of a web app across varied screen resolutions:

Responsive Design – One code base for all devices

Bootstrap implements a fluid grid system. This breaks the screen into columns and uses percentages instead of pixels for column widths. A mobile ArcGIS app built using Bootstrap adapts to different screen sizes using this fluid column...