javascript

Chapter 16: ECMA Script for XML
The child() method behaves in the exact same way as property access. Any property name or index
can be passed into the child() method and it will return the same value. Consider this example:
var firstChild = employees.child(0);
//same as employees.*[0]
var employeeList = employees.child(“employee”); //same as employees.employee
var allChildren = employees.child(“*”);
//same as employees.*
For added convenience, a children() method is provided that always returns all child elements. Here’s
an example:
var allChildren = employees.children(); //same as employees.*
There is also an elements() method, which behaves similar to child() with the exception that it will
return only XML objects that represent elements. For example:
var employeeList = employees.elements(“employee”); //same as employees.employee
var allChildren = employees.elements(“*”);
//same as employees.*
These methods provide a more familiar syntax for JavaScript developers to access XML data.
Child elements can be removed by using the delete operator as shown here:
delete employees.employee[0];
alert(employees.employee.length()); //1
This is one of the major advantages of treating child nodes as properties.
Accessing Attributes
Attributes can also be accessed using dot notation, although the syntax is slightly augmented. To
differentiate an attribute name from a child - element tag name, you must prepend an “ at ” character (@)
before the name. This syntax is borrowed from XPath, which also uses @ to differentiate between
attributes and character names. The result is a syntax that looks a little strange, as you can see in this
example:
var employees = < employees >
< employee position=”Software Engineer” >
< name > Nicholas C. Zakas < /name >
< /employee >
< employee position=”Salesperson” >
< name > Jim Smith < /name >
< /employee >
< /employees > ;
alert(employees.employee[0].@position); //”Software Engineer”
As with elements, each attribute is represented as a property that can be accessed using this shorthand
notation. An XML object representing the attribute is returned and its toString() method always
returns the attribute value. To get the attribute name, use the name() method of the object.
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