Java Reference
In-Depth Information
}
draggedEl.parentNode.removeChild(draggedEl);
this.appendChild(draggedEl);
this.className = "";
After you remove the dragged element from its parent and append it to the drop target, you reach into
your
data
object and alert its
message
to the user:
alert(data.message);
}
This technique of using JSON to store object data is useful in a variety of scenarios. In the next
chapter, you use the same technique to store object data directly in the browser.
summarY
In this chapter, you looked at JSON, a text format for storing and transmitting objects, arrays, and
simple values. Let's look at some of the things discussed in this chapter:
➤
Serialization is the process of translating objects and values into a string representation of
those objects and values.
➤
The web used to use XML for storing and transmitting JavaScript data, but JSON is now the
format of choice.
➤
JSON is not JavaScript, but a subset of JavaScript. Its syntax looks similar, but key differ-
ences exist between the two. For one, JSON does not have variables or functions. It is simply
a data format.
➤
JSON strings must be surrounded by double quotes. Single quotes result in an error.
➤
Numbers, booleans, and
null
appear as literal values in JSON.
➤
JSON objects look very much like JavaScript object literals except their properties are strings
and there are no trailing semicolons.
➤
JSON arrays are almost identical to JavaScript array literals, but they do not have a trailing
semicolon.
➤
You serialize JavaScript objects, arrays, and values using the
JSON
object's
stringify()
method.
➤
You parse JSON text into a JavaScript object or value using
JSON.parse()
.
In the next chapter, you look at how to store data in and for the browser using local storage and
cookies.
