由 JavaScript 为 Google Maps Legend 创建的 html 元素的事件侦听器不起作用

Question

I'm trying to use Javascript to add event listeners to several links that are created via Javascript. I thought that I am probably calling it before it is created but looked at some other examples (such as add event listener on elements created dynamically and Google Map Event Listener does not seem to work ) on here and thought that if those work I should probably be fine as well. If anyone could point out where I'm going wrong it would be greatly appreciated.

*It seems like it would be way easier for everyone to just put the whole snippet in.

Also as of right now I'm getting "P1 [object HTMLParagraphElement]" for when I console.log("P1 " + precinct1

JS Snippet:

    function initialize() {

  var myOptions = {
    zoom: 10,
    center: new google.maps.LatLng(123, 123),
    mapTypeId: google.maps.MapTypeId.ROADMAP
  }

/*
Creating Map - Do not create with Fusion Tables directly so that you have control
of how the polygons are drawn.
*/
map = new google.maps.Map(document.getElementById('map-canvas'), myOptions);

  //Initialize JSONP request

  var script = document.createElement('script');
  var url = ['https://www.googleapis.com/fusiontables/v1/query?'];
  url.push('sql=');
  var query = 'SELECT COMMISH, geometry, Website FROM ' + tableId;
  var encodedQuery = encodeURIComponent(query);
  url.push(encodedQuery);
  url.push('&callback=drawMap');
  url.push('&key=' + key);
  script.src = url.join('');
  var body = document.getElementsByTagName('body')[0];
  body.appendChild(script);
}

  function createPolygon(precinct, url, comPrecinct){
    google.maps.event.addListener(precinct, 'mouseover', function() {
      this.setOptions(
        {
          fillOpacity: 0.5,
          strokeOpacity: 1,
        }
      );

    });

    google.maps.event.addListener(precinct, 'mouseout', function() {
      this.setOptions(
        {
          fillOpacity: 0.3,
          strokeOpacity: 0,
        }
      );
    });

    google.maps.event.addListener(precinct, 'click', function(){
      window.location = url;
    });

  }

  function drawMap(data) {
        var rows = data['rows'];
        console.log(rows);
        /*Create Legend*/
        var legend = document.createElement('div');
        legend.id = 'legend';
        var content = [];
        content.push('<a href="#"><p class="precinct" id="precinct1"></div>Precinct 1</p></a>');
        content.push('<a href="#"><p class="precinct" id="precinct2"></div>Precinct 2</p></a>');
        content.push('<a href="#"><p class="precinct" id="precinct3"></div>Precinct 3</p></a>');
        content.push('<a href="#"><p class="precinct" id="precinct4"></div>Precinct 4</p></a>');

       legend.innerHTML = content.join('');
       legend.index = 1;
       map.controls[google.maps.ControlPosition.RIGHT_TOP].push(legend);

        for (var i in rows) {
            var comPrecinct = rows[i][0];
            var url = rows[i][2];
            var newCoordinates = [];
            var geometries = rows[i][1]['geometries'];

            if (geometries) {
              for (var j in geometries) {
                newCoordinates.push(constructNewCoordinates(geometries[j]));
              }
            } else {
              newCoordinates = constructNewCoordinates(rows[i][1]['geometry']);
            }

            /*
              Colors are out of order because precincts are out of order
              in KML files. Adjust CSS as necessary.
            */
            var precinct = new google.maps.Polygon({
              paths: newCoordinates,
              strokeColor: colors[i],
              strokeOpacity: 0,
              strokeWeight: 1,
              fillColor: colors[i],
              fillOpacity: 0.3,
            });


            createPolygon(precinct, url, comPrecinct);

            precinct.setMap(map);

        }

      console.log('P1 ' + precinct1);
      google.maps.event.addListener(legend, 'hover', function(e){
          if(e.target.id === 'precinct1'){
            console.log("P1 - aawwwww yis");
          }
        });

  }

  function constructNewCoordinates(polygon){
    var newCoordinates = [];
    var coordinates = polygon['coordinates'][0];
    for (var i in coordinates){
      newCoordinates.push(new google.maps.LatLng(coordinates[i][1], coordinates[i][0]));
    }
    return newCoordinates;
  }

google.maps.event.addDomListener(window, 'load', initialize);

P].push(legend);

Answer 1

I don't know much about google maps api, but the code seems a bit weird to me. You add plain HTML text as strings into an array which aren't placed in the dom/your div. Even the document.getElementById('precinct1'); should not work.

You have to append your links into the dom/your div first, after that register the event handler for each item:

legend.innerHTML += content.join('');

var links = legend.getElementsByTagName('p'); // these are your items with the id you want to bind

for(var i = 0; i < links.length; i++) {
    google.maps.event.addListener(links[i], 'hover', function(){
        console.log("Aww yis");
    });
}

If i'm wrong: Feel free to blame me.

Answer 2

The problem is that (as you point it out) you are using it before it is created. Options:

1. Create it (and actually add it to the document), then cache it, then call it.
2. Do not cache it (advise against this)
3. Delegate from the container they are added in (preferred)

I have not used the Google Maps API, but something like this might work (assuming it captures the same mouse event:

google.maps.event.addListener(precinctContainer, 'hover', function(e){
    if(e.target.id === 'precinct1'){
        console.log("Aww yis");
    }
});

Where precinctContainer is the container you put all those <a> tags in the content array.