在Arcgis JavaScript Api中，可以使用Graphic类和Feature Layer类来实现特效和混合功能的高亮特征。

下面是一个使用Feature Layer类来高亮选定区域的示例代码：

var highlightSymbol = {
   "color": [255,255,0,128],
   "outline": {
     "color": [255,0,0,255],
     "width": 1,
     "type": "esriSLS",
     "style": "esriSLSSolid"
   },
   "type": "esriSFS",
   "style": "esriSFSForwardDiagonal"
 };
  
 var featureLayer = new FeatureLayer("https://sampleserver6.arcgisonline.com/arcgis/rest/services/Census/MapServer/3", {
   mode: FeatureLayer.MODE_SNAPSHOT,
   outFields: ["*"]
 });
 map.addLayer(featureLayer);
  
 var highlightGraphics = [];
 on(element, "click", function(evt){
   featureLayer.clearSelection();
   highlightGraphics = [];
   var query = new Query();
   query.geometry = pointToExtent(map, evt.mapPoint, 10);
   var deferred = featureLayer.selectFeatures(query, FeatureLayer.SELECTION_NEW);
   deferred.then(function(selection){
     arrayUtils.forEach(selection, function(feature){
       feature.setSymbol(highlightSymbol);
       highlightGraphics.push(feature);
     });
   });
 });
  
 on(element, "mousemove", function(evt){
   var highlight = false;
   arrayUtils.forEach(highlightGraphics, function(graphic){
     graphic.setSymbol(highlightSymbol);
     if(graphic.geometry.contains(evt.mapPoint)){
       highlight = true;
     }
   });
   map.setMapCursor(highlight ? "pointer": "default");
 });

这段代码首先定义了一个highlightSymbol变量，它包括一个颜色（黄色与半透明），轮廓线条（红色）和样式（斜线填充）。

接下来，我们创建一个Feature Layer类的实例，并将其添加到地图上。然后我们定义了一个空数组highlightGraphics来保存高亮