Access and secure data - Programming in HTML5 with JavaScript and CSS3 - page 223

When the data is received via the XMLHttpRequest object, the data will need to be
deserialized into a more user-friendly format. You also might want to submit data to the
server in response to user actions. The next objective examines these concepts.

Thought experiment

Creating a webpage with a stock ticker

In this thought experiment, apply what you've learned about this objective. You can
find answers to these questions in the “Answers” section at the end of this chapter.

You are tasked with building a webpage for your client that involves a stock ticker.
You need to provide real-time stock quotes to your page users in a scroll across the
top of the page. Explain how you would build a web application that will do this
dynamically without posting back the whole webpage.

Objective summary
■ JSON and XML are the most common formats used for data exchange.
■ JSON consists of name/value pairs.
■ XML is a structured element-based document.
■ JavaScript provides built-in support for receiving data via the XMLHttpRequest object.

Objective review

Which of the following is a valid JSON string? 1.

A. {firstName, Rick, lastname, Delorme, hairColor, brown, eyeColor, brown}

B. {firstName: Rick; lastname: Delorme; hairColor: brown; eyeColor: brown}

C. {firstName: “Rick”; lastname: “Delorme”; hairColor: “brown”; eyeColor: “brown”}

D. {firstName: “Rick”, lastname: “Delorme”, hairColor: “brown”, eyeColor: “brown”}

With the XMLHttpRequest object, which of the following properties provides the
response in a human readable format?

2.

A. Response

B. responseBody

C. responseText

D. responseXML