javascript - Call method whenever form field is typed in -

i have form includes dropdown. user can either select option dropdown in turn fills form field in question, or user can type choice manually form field. want make sure dropdown resets upon user typing in form field. i'm thinking sort of click handler, know ng-click not appropriate here.

<form class="form-inline" name="tagform">   <div class="form-group">     <isteven-multi-select       input-model="header.tagnames"       output-model="tagsoutput"       button-label="name"       item-label="name"       tick-property="ticked"       selection-mode="single"       on-item-click="header.selecttag(data)">     </isteven-multi-select>   </div>   <div class="form-group">     <input class="form-control" type="text" id="tag" placeholder="tag" ng-model="header.newtag.tag" ng-required="true">   </div> 

so example, user selects 'passed' dropdown, rethinks decision , clicks in form field delete 'passed' , type in 'failing'. user begins typing (or clicks delete, keystroke) dropdown should reset no field selected. how call method within form field whenever keystroke occurs in field?