angularjs 如何找子级元素，如下代码没有fing方法，求指教！

我本飞扬521

<div class="jmhYjxDZ" ng-click="jmhYjbDz($event)"><img src="../common/imgs/dz-n.png"><div class="czText">赞</div></div>
$scope.jmhYjbDz = function (obj){
  // obj.target.setAttribute("src","../common/imgs/dz-y.png")
  alert(obj.target.find("img"));

}