Question

I have problem with javascript code. I am using google maps and I am collecting data trough from server in json format. When I check data in console window in some browser I can see that data is actually coming.

My problem is that variable is read once and I am showing it’s value in the textbox. Now when I keep receiving data variable is always the same, any idea why? And I am 100% sure that I am getting different values.

Here is the code:

function updateTrucks() {
    $.ajax({
        url: "get_data.php",
        cache: false,
        dataType: 'json',
        data: {},
        error: function(jqxhr, textStatus, errorThrown) {
            alert("Error: " + textStatus + " " + errorThrown);
        },
        success: function(data) {
        for(var i = 0; i < data.results.length; i++) {
            if(trucks.hasOwnProperty(data.results[i].id)) {
                // update position
                trucks[data.results[i].id].setPosition(new google.maps.LatLng(
                parseFloat(data.results[i].lat),
                parseFloat(data.results[i].lng)));
                trucks[data.results[i].id].speed = data.results[i].speed;
            }
            else {
                // code
            }

            google.maps.event.addListener(trucks[data.results[i].id], 'position_changed', function() {
                if(typeof tracked !== "undefined") {
                    if(this.id == tracked.id) {
                        map.panTo(this.getPosition());
                        $("#speed").val(this.speed);
                    }
                }
            });     

This line is not working correctly $("#speed").val(this.speed);

Answer 1

I think you need change order of you commands while updating position, so when position_changed fired speed property will be refreshed:

if(trucks.hasOwnProperty(data.results[i].id)) {
                trucks[data.results[i].id].speed = data.results[i].speed;
                // update position
                trucks[data.results[i].id].setPosition(new google.maps.LatLng(
                  parseFloat(data.results[i].lat),
                  parseFloat(data.results[i].lng)));
              }