<div class="form-group col-lg-6">
       <div class="input-group col-md-6">
         <span class="input-group-addon">
           <i class="glyphicon glyphicon-search"></i>
          </span>
         <input type="text" class="form-control" required="" placeholder="Search the group" ng-model="searchDatalocation" ng-change="searchUsers()" name="searchValue">
         </div>
      </div>

<span style="color:red" ng-show="submitted == true && mainForm.searchValue.$error.required">Data is required</span>