Peter Lubbers - Pro HTML 5 Programming

Figure 1-3. Developer Tools view in Chrome
CHAPTER 1 ■ OVERVIEW OF HTML5
Many of the debugging tools offer a way to set breakpoints to halt code execution and analyze the
state of the program and the current state of the variables. The console.log API has become the de facto
logging standard for JavaScript developers. Many browsers offer a split-pane view that allows you to see
messages logged to the console. Using console.log is much better than making a call to alert(), since it
does not halt program execution.
window.JSON
JSON is a relatively new and increasingly popular way to represent data. It is a subset of JavaScript syntax
that represents data as object literals. Due to its simplicity and natural fit in JavaScript programming,
JSON has become the de facto standard for data interchange in HTML5 applications. The canonical API
for JSON has two functions, parse() and stringify() (meaning serialize or convert to string).
To use JSON in older browsers, you need a JavaScript library (several can be found at
http://json.org). Parsing and serializing in JavaScript are not always as fast as you would like, so to
speed up things, newer browsers now have a native implementation of JSON that can be called from
JavaScript. The native JSON object is specified as part of the ECMAScript 5 standard covering the next
generation of the JavaScript language. It is one of the first parts of ECMAScript 5 to be widely
implemented. Every modern browser has window.JSON, and you can expect to see quite a lot of JSON
used in HTML5 applications.
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