Change bootstrap form based on the users active input. Display a change in the form only based on the text entered and no button clicks

Question

Like credit card logo pops up as you enter in your credit card number. Instead of a logo I want to display a change in the form without a button click. Form automatically detects change after the input field has been filled.

Answer 1

Simple example:

In Angularjs

 $scope.changeStyle=function(){ $scope.color="red"; } 

  <form> <div class="form-group"> <label for="exampleInputEmail1">Email address</label> <input type="email" class="form-control" ng-model="someName" ng-change="changeStyle()" id="exampleInputEmail1" ng-style="{'color':color}" placeholder="Email"> </div> <button type="submit" class="btn btn-default">Submit</button> </form>