Edit in JSFiddle

var app = angular.module('form-example1', []);
 
var INTEGER_REGEXP = /^\-?\d*$/;
app.directive('integer', function() {
  return {
    require: 'ngModel',
    link: function(scope, elm, attrs, ctrl) {
      ctrl.$parsers.unshift(function(viewValue) {
        if (INTEGER_REGEXP.test(viewValue)) {
          // it is valid
          ctrl.$setValidity('integer', true);
          return viewValue;
        } else {
          // it is invalid, return undefined (no model update)
          ctrl.$setValidity('integer', false);
          return undefined;
        }
      });
    }
  };
});
 
var FLOAT_REGEXP = /^\-?\d+((\.|\,)\d+)?$/;
app.directive('smartFloat', function() {
  return {
    require: 'ngModel',
    link: function(scope, elm, attrs, ctrl) {
      ctrl.$parsers.unshift(function(viewValue) {
        if (FLOAT_REGEXP.test(viewValue)) {
          ctrl.$setValidity('float', true);
          return parseFloat(viewValue.replace(',', '.'));
        } else {
          ctrl.$setValidity('float', false);
          return undefined;
        }
      });
    }
  };
});
function Controller(){
}

  <div ng-controller="Controller">
      <form name="form" class="css-form" novalidate>
        <div>
          Size (integer 0 - 10):
          <input type="number" ng-model="size" name="size"
                 min="0" max="10" integer />{{size}}<br />
          <span ng-show="form.size.$error.integer">This is not valid integer!</span>
          <span ng-show="form.size.$error.min || form.size.$error.max">
            The value must be in range 0 to 10!</span>
        </div>
    
        <div>
          Length (float):
          <input type="text" ng-model="length" name="length" smart-float />
          {{length}}<br />
          <span ng-show="form.length.$error.float">
            This is not a valid float number!</span>
        </div>
      </form>
    </div>