google maps: load embedded iframe with direction via form

see:http://stackoverflow.com/questions/18687603/how-to-get-google-maps-route-planner-on-websites-iframe

by Tsuneo Yoshioka

HTML

<form method="get" action="https://www.google.com/maps" target="mapframe">
            <input name="saddr" type="text" id="saddr">
            <input name="output" type="hidden" value="embed">
            <input name="f" type="hidden" value="d">
            <input name="z" type="hidden" value="11">
            <input name="daddr" type="hidden" id="daddr" 
                   value="Empire State Building, 350 5th Avenue, New York, NY, USA">
            <input type="submit" name="Submit" value="Submit">
    </form>
    <iframe name="mapframe" width="425" height="350" 
            src="https://www.google.com/maps?z=11&amp;f=d&amp;output=embed&amp;ll=40.7902,-73.9597">
    </iframe>