Colophon

The animal on the cover of Building Isomorphic JavaScript Apps is the gray tree frog (Hyla versicolor), a small frog native to eastern and central North America. The gray tree frog is so named for its arboreal habitat and gray coloring. However, as its scientific name would suggest, the gray tree frog has the ability to change its color from gray to green, much like a chameleon. This ability is used as camouflage to evade predators.

The gray tree frog can be found in forested regions as far south as Texas and as far north as New Brunswick. They rarely venture from their treetop homes except to breed. Gray tree frogs grow to about two inches in length and have lumpy skin like a toad (hence their nickname, the changeable toad). Their diet consists of a variety of insects, such as crickets, grasshoppers, and ants.

There are no major threats to the gray tree frog, and their population is believed to be stable. Gray tree frogs are sometimes kept as pets and live five to ten years.

Many of the animals on O’Reilly covers are endangered; all of them are important to the world. To learn more about how you can help, go to animals.oreilly.com.

The cover image is from Wood’s Illustrated Natural History. The cover fonts are URW Typewriter and Guardian Sans. The text font is Adobe Minion Pro; the heading font is Adobe Myriad Condensed; and the code font is Dalton Maag’s Ubuntu Mono.