angularjs simple controller

HTML

<script src="http://ajax.googleapis.com/ajax/libs/angularjs/1.2.26/angular.min.js"></script>
<div ng-app="app">
    <p>Try to change the names.</p>
    <div ng-controller="personController">
        <p>
            First Name:
            <input type="text" ng-model="firstName" ng-blur="check(firstName)" pattern="^[+-]?[0-9]{1,9}(?:\.[0-9]{1,2})?$" />
       
    </div>
</div>

JavaScript

angular.module("app", []).controller("personController", function($scope) {
  var pattern = /^\d*$/;
			/* 	if(scope.attributeVal){
				  var allowNegative = scope.attributeVal.allowNegative !== undefined ? scope.attributeVal.allowNegative : false;
				  if(allowNegative) pattern = '^[-|[0-9]][0-9]*$';
				  var allowDecimal = scope.attributeVal.allowDecimal !== undefined ? scope.attributeVal.allowDecimal : true;
				  if(allowDecimal){ 
				    pattern = pattern.slice(0, -1);
				    pattern += '(\.[0-9]{2}?)?';
				  }
				} */
			var regexPattern = new RegExp(pattern, "g");	
			
      
      $scope.check=function(input)
      {
    		 var clean = input.replace(pattern, ""); 
      	if (input !== clean) {
        console.log(clean);
        alert(clean)
        }
      }
});