the code in the same script tag work well, but calling the function that contains the same code from other script tag doesn't

as I described in the title.

in my code I have a google map script in the header and it works very well let's call this script tag (A).

the problem is that when I'm not in the script tag A and want to call a function that is in the script A from another script tag to reuse it. it will not work. however if I copied the code from that function and put it directly in the same tag it will work.

I want to be able to call it not to write it again. what is the wrong thing in my code??

here is my code

the script A (the one in the head tag)

<script>
    //this is the function that I want call
    function getAddress(location) {
        var geocoder = new google.maps.Geocoder();
        var latLng = new google.maps.LatLng(location.lat(), location.lng());
        geocoder.geocode({
            latLng: latLng
        },
            function (responses) {
                if (responses && responses.length > 0) {
                    $("#addressResult").text(responses[0].formatted_address);
                    // alert(responses[0].formatted_address);
                } else {
                    alert('Caot determine address at this location.');
                }
            });
    }
    var map;
    var myCenter = new google.maps.LatLng(51.508742, -0.120850);

    function initialize() {
        var mapProp = {
            center: myCenter,
            zoom: 5,
            mapTypeId: google.maps.MapTypeId.ROADMAP
        };

        map = new google.maps.Map(document.getElementById("googleMap"), mapProp);

        google.maps.event.addListener(map, 'click', function (event) {
            placeMarker(event.latLng);

        });

    }
    var marker
    function placeMarker(location) {
        if (marker) {
            marker.setPosition(location);
        } else {
            marker = new google.maps.Marker({
                position: location,
                map: map
            });
        }
        //here
        getAddress(location);

    }

    google.maps.event.addDomListener(window, 'load', initialize);
</script>

and here where I want call it

<script>
                            var x = document.getElementById("addressResult");
                            function getLocation() {
                                if (navigator.geolocation) {
                                    navigator.geolocation.getCurrentPosition(showPosition);
                                } else {
                                    x.ierHTML = "Geolocation is not supported by this browser.";
                                }
                            }

                            function showPosition(position) {
                               //here where I want to call it
                                getAddress(position);
                                }
</script>