Creates a Drupal Ajax 'data' command.
The 'data' command instructs the client to attach the name=value pair of data to the selector via jQuery's data cache.
This command is implemented by Drupal.ajax.prototype.commands.data() defined in misc/ajax.js.
$selector: A jQuery selector string. If the command is a response to a request from an #ajax form element then this value can be NULL.
$name: The name or key (in the key value pair) of the data attached to this selector.
$value: The value of the data. Not just limited to strings can be any format.
An array suitable for use with the ajax_render() function.
http://docs.jquery.com/Core/data#namevalue
function ajax_command_data($selector, $name, $value) {
return array(
'command' => 'data',
'selector' => $selector,
'name' => $name,
'value' => $value,
);
}