Edit in JSFiddle

<script src="https://maps.googleapis.com/maps/api/js?v=3.exp"></script>
<div>1</div>
<div>2</div>
<div>3</div>
<div>4</div>
<div id="googft-mapCanvas"></div>

// This example displays a marker at the center of Australia.
// When the user clicks the marker, an info window opens.
// The maximum width of the info window is set to 200 pixels.

function initialize() {
    var myLatlng = new google.maps.LatLng(-25.363882, 131.044922);
    var mapOptions = {
        zoom: 4,
        center: myLatlng
    };

    var map = new google.maps.Map(document.getElementById('googft-mapCanvas'), mapOptions);

    var contentString = '<div id="content">hello</div>';

    var infowindow = new google.maps.InfoWindow({
        content: contentString,
        maxWidth: 200
    });

    var marker = new google.maps.Marker({
        position: myLatlng,
        map: map,
        title: 'Uluru (Ayers Rock)'
    });

    google.maps.event.addListener(marker, 'mouseover', function () {
        infowindow.open(map, marker);
    });
    google.maps.event.addListener(marker, 'mouseout', function () {
        infowindow.close();
    });
}

google.maps.event.addDomListener(window, 'load', initialize);

html, body, #googft-mapCanvas {
     height: 100%;
     margin: 0;
     padding: 0;
}