JS field doesn't accept Google Maps API library for external resources. (I'm not sure why) So you need to insert <script>tag into the body field.

And JS field generates "window.onload" automatically. You don't have to write "google.maps.event.addDomListener" in JS field.

http://jsfiddle.net/wf9a5m75/NpYwE/27/

<div id="panel" style="margin-left: -260px">
    <input id="searchTextField" type="text" size="50">
    <input type="radio" name="type" id="changetype-all" checked="checked">
    <label for="changetype-all">All</label>
    <input type="radio" name="type" id="changetype-establishment">
    <label for="changetype-establishment">Establishments</label>
    <input type="radio" name="type" id="changetype-geocode">
    <label for="changetype-geocode">Geocodes</lable>
</div>
<div id="map-canvas"></div>
        <script src="http://maps.google.com/maps/api/js?sensor=false&libraries=places"></script>

It looks like there is no convenient UI for just querying it from the web. Instead, just consult the Places API documentation, and paste a query of the following style, for example, into your browser address bar.

https://maps.googleapis.com/maps/api/place/findplacefromtext/json?key=YOUR_API_KEY&inputtype=textquery&input=Starbucks