ngpattern

HTML

<div ng-controller="MyCtrl">
  <form name="myForm" ng-submit="onSubmit()">
    <br>
    <textarea class="text-list-area" ng-model="input" name="input_field" ng-pattern="/^((([^;]+);([^;]*);([^;]+))\n?)*$/" rows="10" cols="60"></textarea>
    <span ng-show="myForm.input_field.$error.pattern">Not a valid input!</span>

    <input type="submit" value="submit" />
  </form>
</div>

JavaScript

var myApp = angular.module('myApp', []);

myApp.controller("MyCtrl", function($scope) {
		$scope.input="value1;value2;value3\nvalue1"
});