对象没有方法“charAt”

Question

I'm using the following function to get the elevation on Google Maps:

function getElevation(event) {
    var locations = [];
    var clickedLocation = event.latLng;
    locations.push(clickedLocation);

    var positionalRequest = {
        'locations': locations
    }

    elevator.getElevationForLocations(positionalRequest, function(results, status) {
        if(status == google.maps.ElevationStatus.OK) {
            var s = results[0].elevation;

            if(results[0]) {
                $('#elevation').html(parseInt(s).charAt(0) + ' meter');
            } else {
                alert('Inget resultat hittades');
            }
        } else {
            alert('Det gick inte att hitta höjdskillnaden på grund av följande: ' + status);
        }
    });
}

I'm getting Uncaught TypeError: Object 65 has no method 'charAt' when I click somewhere on the map and I don't know how I shall fix this problem. parseInt(s) prints for example 44 depending on where you click on the map. If I click on the ocean it shows for example -4837 and it's just that minus character I want to identify if it's exists in this string.

Any ideas of how I can fix this problem?

Thanks in advance.

Answer 1

Numbers don't have a "charAt()" method on their prototype, but strings do.

$('#elevation').html(('' + parseInt(s)).charAt(0) + ' meter');

The parseInt() function returns a number. You have to explicitly convert it to a string first.

Why it is that you're trying to make it a number in the first place is a little mysterious.

Answer 2

parseInt(s).charAt(0)

You are parsing a string and returning an integer, and then trying to call charAt on an integer, which won't work too well. You should call charAt before you parse it.