how to get polygon base on a point arcgis javascript api

[lasinh]

i have layer type polygon,   how to select polygon containing a point(a point inside  polygon, )

[TimWitt2]

You can use something like this  

var allPoints = [];
  var mp = new Multipoint(); 
  arrayUtils.map(YourPointLayer.graphics, function(gra){ 
  mp.addPoint(gra.geometry); 
  allPoints.push(gra);
  }); 
  mp.spatialReference = YourPointLayer.graphics[0].geometry.spatialReference;


  var query = new Query();

  query.geometry = mp;

  YourPolygonLayer.selectFeatures(query);