Google MAP API Uncaught TypeError: Cannot read property 'offsetWidth' of null

Question

This problem is usually due to the map div not being rendered before the javascript runs that needs to access it.

You should put your initialization code inside an onload function or at the bottom of your HTML file, just before the tag, so the DOM is completely rendered before it executes (note that the second option is more sensitive to invalid HTML).

Note, as pointed out by matthewsheets this also could be cause by the div with that id not existing at all in your HTML (the pathological case of the div not being rendered)

Adding code sample from wf9a5m75's post to put everything in one place:

<script type="text/javascript">

function initialize() {
    var latlng = new google.maps.LatLng(-34.397, 150.644);
    var myOptions = {
        zoom: 8,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    var map = new google.maps.Map(document.getElementById("map_canvas"),
            myOptions);
}
google.maps.event.addDomListener(window, "load", initialize);

</script>

For others that might still be having this issue, even after trying the above recommendations, using an incorrect selector for your map canvas in the initialize function can cause this same issue as the function is trying to access something that doesn't exist. Double-check that your map Id matches in your initialize function and your HTML or this same error may be thrown.

In other words, make sure your IDs match up. ;)

You can also get this error if you don't specify center or zoom in your map options.

google uses id="map_canvas" and id="map-canvas" in the samples, double-check and re-double-check the id :D

Year, geocodezip's answer is correct. So change your code like this: (if you still in trouble, or maybe somebody else in the future)

<script type="text/javascript">

function initialize() {
    var latlng = new google.maps.LatLng(-34.397, 150.644);
    var myOptions = {
        zoom: 8,
        center: latlng,
        mapTypeId: google.maps.MapTypeId.ROADMAP
    };
    var map = new google.maps.Map(document.getElementById("map_canvas"),
            myOptions);
}
google.maps.event.addDomListener(window, "load", initialize);

</script>

Just so I add my fail scenario in getting this to work. I had a <div id="map> in which I was loading the map with:

var map = new google.maps.Map(document.getElementById("map"), myOptions);

and the div was initially hidden and it didn't have explicitly width and height values set so it's size was width x 0. Once I've set the size of this div in CSS like this

#map {
    width: 500px;
    height: 300px;
}

everything worked! Hope this helps someone.

For even more others that might still be having this issue, I was using a self-closing <div id="map1" /> tag, and the second div was not showing, and did not seem to be in the dom. as soon as i changed it to two open&close tags <div id="map1"></div> it worked. hth