There's an app called Textastic that let's you code in many languages, but if you are doing HTML then you can actually run/preview the page, and it will also li

There's an app called Textastic that let's you code in many languages, but if you are doing HTML then you can actually run/preview the page, and it will also link to resources in the same folder, like JavaScript or CSS files. There's also Code2Go which sends your code to a server and returns the output. It has shells/compilers for many languages.