javascript - cannot read property 'addeventlistener' of null using Google Place Autocomplete API -

javascript - cannot read property 'addeventlistener' of null using Google Place Autocomplete API -

i have problem trying implement google place autocomplete api. have been working in asp.net c# project. when typing place name in textbox, shows place option. however, when selecting alternative not show location on map first time, when select sec time, show on map.

i debugged javascript, , shows error cannot read property 'addeventlistener' of null.

here code have tried:

function initialize() { var mapoptions = { center: new google.maps.latlng(28.669156500000000000, 77.453757799999950000), zoom: 13, maptypeid: google.maps.maptypeid.roadmap }; var input = document.getelementbyid('txtpickuppoints'); var map = new google.maps.map(document.getelementbyid('gmap1'), mapoptions); var autocomplete = new google.maps.places.autocomplete(input); autocomplete.bindto('bounds', map); google.maps.event.addlistener(autocomplete, 'place_changed', function () { var place = autocomplete.getplace(); if (place.geometry.viewport) { map.fitbounds(place.geometry.viewport); } else { map.setcenter(place.geometry.location); map.setzoom(17); } }); //document.getelementbyid("lbl_lati").innerhtml = "good going"; //document.getelementbyid("lbl_longi").innerhtml = document.getelementbyid('textbox1').value = gmap1.get.lng(); } google.maps.event.adddomlistener(window, 'load', initialize); using <script type="text/javascript" src="http://maps.googleapis.com/maps/api/js? sensor=false&libraries=places"></script>

javascript c# asp.net google-maps-api-3 google-places-api