Introduction to E4X
E4X is a JavaScript extension that enables you to manipulate XML objects directly in scripts.
This document deals with the most common concepts used. For more information, refer to the ECMA-357 specification: http://www.ecma-international.org/publications/standards/Ecma-357.htm.
XML type
var myXml = <root>
<item id="1"/>
<item id="2">
text
</item>
</root>
Substitution
var myTag = "delivery"
var myXml = <{myTag} id="42">Hello</{myTag}>
var myValue = "123"
var myXml = <toto id={myValue}>Hello</toto>
var myContent = "Hello"
var myXml = <toto id="123">{myContent}</toto>
var mySubXml = <b>world</b>
var myXml = <toto id="123">Hello {mySubXml}</toto>
Accessors
Returns the name of the element
myXml.name()
Returns the parent or null
myXml.parent()
Access an attribute or text of an element
var myXml =
<article id="123" operator-id="456">
<title>Hello</title>
My Content
</article>
myXml.@id // "123"
myXml.@['operator-id'] // "456"
myXml.title // "Hello"
Test for an attribute or a sub-element.
myXml.attribute('id').length() == 0 // attribute is missing
myXml.child('title').length() == 0 // element is missing
Enumeration
var myXml = <root><item id="1"/><item id="2"/></root>
for each (var x in myXml.item)
logInfo(x.@id)
Insertion
myXml.appendChild(<something id="1"/>blah blah</something>)
Search
Retrieve the list of employees named 'John':
var john = e.employee.(name == "John")
Retrieve the list of employees with ID 0 or 1:
var twoemployees = e.employee.(@id == 0 || @id == 1)
Retrieve the name of employee with identifier 1:
var emp = e.employee.(@id == 1).name
Conversion
var str = myXml.toXMLString()
var myXml = new XML(str)
Miscellaneous
typeof(<toto/>) // "xml"