/demo.html

## demo.html
<html ng-app="myApp">
<head>
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
<script>
var myApp = angular.module("myApp",[]) ;
myApp.controller('MyCtrl', ['$scope', function($scope) {
	$scope.formModel = {};

}]);
myApp.directive('mutuallyExclusive', function() {
return {
	require: 'ngModel',
    	link: function(scope, elem, attrs, ctrl) {
        	var xorValidator = function(value) {
        		var form = scope[attrs.form];
        		var theOther = form[attrs.mutuallyExclusive];
        		var otherValue = theOther.$modelValue;


        		var a = (value != null && typeof(value) !== 'undefined' && value != '') ? true: false;

        		var b = (otherValue != null && typeof(otherValue) !== 'undefined' && otherValue != '') ? true: false;

        		var xor = ( a || b ) && !( a && b );

				console.log("XOR = " + xor);

				ctrl.$setValidity('field', xor);
        		theOther.$setValidity('field', xor);
        		return value;
    		};
        	ctrl.$parsers.unshift(xorValidator);
   	}
};
});
</script>
</head>
<body ng-controller="MyCtrl">
<form id="myForm" name="myForm" method="post" novalidate="novalidate">
	<select id="select1" name="select1" form="myForm" ng-model="formModel.select1" mutually-exclusive="text1">
		<option value="0">Value 0</option>
		<option value="1">Value 1</option>
	</select>
	<input type="number" id="text1" name="text1" form="myForm" ng-model="formModel.text1" mutually-exclusive="select1"/>
	<input type="submit" ng-disabled="myForm.$invalid || (myForm.select1.$pristine && myForm.text1.$pristine)" />
</form>

myForm.$invalid: {{myForm.$invalid}}<br />
{{myForm.text1.$pristine}}
<pre>select1.$invalid: {{myForm.select1 | json}}
</pre>
<pre>text1.$invalid: {{myForm.text1 | json}}</pre>
</body>
</html>
	<html ng-app="myApp">
	<head>
	<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.3.14/angular.min.js"></script>
	<script>
	var myApp = angular.module("myApp",[]) ;
	myApp.controller('MyCtrl', ['$scope', function($scope) {
	$scope.formModel = {};

	}]);
	myApp.directive('mutuallyExclusive', function() {
	return {
	require: 'ngModel',
	link: function(scope, elem, attrs, ctrl) {
	var xorValidator = function(value) {
	var form = scope[attrs.form];
	var theOther = form[attrs.mutuallyExclusive];
	var otherValue = theOther.$modelValue;


	var a = (value != null && typeof(value) !== 'undefined' && value != '') ? true: false;

	var b = (otherValue != null && typeof(otherValue) !== 'undefined' && otherValue != '') ? true: false;

	var xor = ( a \|\| b ) && !( a && b );

	console.log("XOR = " + xor);

	ctrl.$setValidity('field', xor);
	theOther.$setValidity('field', xor);
	return value;
	};
	ctrl.$parsers.unshift(xorValidator);
	}
	};
	});
	</script>
	</head>
	<body ng-controller="MyCtrl">
	<form id="myForm" name="myForm" method="post" novalidate="novalidate">
	<select id="select1" name="select1" form="myForm" ng-model="formModel.select1" mutually-exclusive="text1">
	<option value="0">Value 0</option>
	<option value="1">Value 1</option>
	</select>
	<input type="number" id="text1" name="text1" form="myForm" ng-model="formModel.text1" mutually-exclusive="select1"/>
	<input type="submit" ng-disabled="myForm.$invalid \|\| (myForm.select1.$pristine && myForm.text1.$pristine)" />
	</form>

	myForm.$invalid: {{myForm.$invalid}}<br />
	{{myForm.text1.$pristine}}
	<pre>select1.$invalid: {{myForm.select1 \| json}}
	</pre>
	<pre>text1.$invalid: {{myForm.text1 \| json}}</pre>
	</body>
	</html>