Javascript makes heavy use of anonymnous function callbacks, which can be saved
within JSON object variables. Still they only work if not
returned inside double qoutes, which Zend_Json naturally does.
With the Expression support for Zend_Json support you can encode
JSON objects with valid javascript callbacks. This works for both
json_encode() or the internal encoder.
A javascript callback is represented using the Zend_Json_Expr
object. It implements the value object pattern and is immutable. You can set the
javascript expression as the first constructor argument. By default
Zend_Json::encode does not encode javascript callbacks, you have
to pass the option enableJsonExprFinder and set it to
TRUE into the encode() function. If
enabled the expression support works for all nested expressions in large object
structures. A usage example would look like:
<?php
$data = array(
'onClick' => new Zend_Json_Expr('function() {'
. 'alert("I am a valid javascript callback '
. 'created by Zend_Json"); }'),
'other' => 'no expression',
);
$jsonObjectWithExpression = Zend_Json::encode(
$data,
false,
array('enableJsonExprFinder' => true)
);