Marker

<!--
  示例：添加标记
  核心逻辑：用 maplibregl.Marker 在城市坐标上放标记，可批量添加与清空
  依赖：MapLibre GL JS 4 · jsDelivr CDN · demotiles 免 Key 样式
-->
<!DOCTYPE html>
<html lang="zh-CN">
<head>
<meta name="robots" content="noindex,follow">
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1">
<title>添加标记</title>
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/maplibre-gl@4/dist/maplibre-gl.css">
<style>
  html,body{height:100%;margin:0}
  body{display:flex;flex-direction:column;overflow:hidden;
       font:13px/1.6 -apple-system,"Segoe UI","PingFang SC",sans-serif;color:#16181d}
  .bar{flex:0 0 auto;display:flex;gap:10px;align-items:center;padding:8px 12px;
       background:#f6f7f9;border-bottom:1px solid #e3e6ea;font-size:12px;color:#58606e;flex-wrap:wrap}
  .bar button{font:inherit;font-size:12px;padding:4px 10px;border-radius:4px;cursor:pointer;
       border:1px solid #ccd1d9;background:#fff;color:#16181d}
  .bar button:hover{background:#eef0f3}
  .bar b{color:#16181d;font-weight:600}
  #map{flex:1 1 auto;min-height:0}
</style>
</head>
<body>
<div class="bar">
  <button id="add">放置标记</button>
  <button id="clear">清空</button>
  <span>共 <b id="n">0</b> 个标记</span>
  <span id="msg">点击标记查看名称</span>
</div>
<div id="map"></div>
<script src="https://cdn.jsdelivr.net/npm/maplibre-gl@4/dist/maplibre-gl.js"></script>
<script>
(function () {
  'use strict';

  if (typeof maplibregl === 'undefined') {
    document.body.innerHTML =
      '<div style="padding:24px;color:#b42318">MapLibre 加载失败，请检查能否访问 cdn.jsdelivr.net</div>';
    return;
  }

  var map = new maplibregl.Map({
    container: 'map',
    style: 'https://demotiles.maplibre.org/style.json',
    center: [108.5, 34.5],
    zoom: 3,
    attributionControl: {
      compact: true,
      customAttribution: 'MapLibre demo tiles'
    }
  });

  var cities = [
    { name: '北京', c: [116.391, 39.907], color: '#1f5fd0' },
    { name: '上海', c: [121.474, 31.230], color: '#c2410c' },
    { name: '广州', c: [113.264, 23.129], color: '#17694a' },
    { name: '成都', c: [104.066, 30.572], color: '#7c3aed' },
    { name: '乌鲁木齐', c: [87.617, 43.792], color: '#a16207' },
    { name: '哈尔滨', c: [126.642, 45.756], color: '#0e7490' }
  ];

  var markers = [];

  function addMarkers() {
    clearMarkers();

    cities.forEach(function (city) {
      var m = new maplibregl.Marker({ color: city.color })
        .setLngLat(city.c)
        .addTo(map);

      m.getElement().addEventListener('click', function () {
        document.getElementById('msg').textContent =
          city.name + ' · ' + city.c[0].toFixed(3) + ', ' + city.c[1].toFixed(3);
      });

      markers.push(m);
    });

    document.getElementById('n').textContent = markers.length;
  }

  function clearMarkers() {
    markers.forEach(function (m) { m.remove(); });
    markers = [];
    document.getElementById('n').textContent = '0';
    document.getElementById('msg').textContent = '点击标记查看名称';
  }

  document.getElementById('add').addEventListener('click', addMarkers);
  document.getElementById('clear').addEventListener('click', clearMarkers);

  map.addControl(new maplibregl.NavigationControl(), 'top-right');
  addMarkers();
})();
</script>
</body>
</html>