The javascript code necessary for the radio buttons to work, has been duplicated and placed substantially unchanged among templates isis, protostar and beez3.

1. administrator/templates/isis/js/template.js
2. templates/protostar/js/template.js
3. templates/beez3/javascript/template.js

The original code suffered a bug which prevents the OnChange JavaScript event to be thrown.
Over time, the 'change' event trigger has been added to isis version here by @bembelimen and to protostar version here by @Minei3oat and they hopefully can review and confirm this PR.

This PR ports the same fix to the beez3 template.

Summary of Changes

Testing Instructions

Put some HTML+JavaScript code to show the onchange event into an article. The following code is fine for that purpose.
Tip: Note that you need to use Editor:none as back-end editor to actually add the code, otherwise javascript code could be stripped out during article save.

<div class="controls">
	<fieldset id="jform_offline" class="btn-group btn-group-yesno btn-group-reversed radio">
		<input type="radio" id="jform_offline0" name="jform[offline]" value="1"/>
		<label for="jform_offline0">Yes </label>
		<input type="radio" id="jform_offline1" name="jform[offline]" value="0" checked="checked"/>
		<label for="jform_offline1">No </label>
	</fieldset>
</div>

<script>
	jQuery('input[type=radio][name="jform[offline]"]').change(function () {
		alert('The value has changed. New value: ' + this.value);
	});
</script>

Expected result

When I change the value to the radio button in the back-end, an alert should notify that the event has been raised.

Actual result

While it works as expected for protostar template, it doesn't on beez3 template.
On beez3 template when user clicks on the radio control (the cue ball) the change event is raised, but when the user clicks on the radio button label, the value changes without raising the onchange event.