marcofiset/angular.js

## angular.js
function Scope() {
    var self = this;

    self.$$watchers = [];

    self.$watch = function(watcherFn, listenerFn) {
        self.$$watchers.push({
            watcherFn: watcherFn,
            listenerFn: listenerFn
        });
    };

    self.$digest = function() {
        self.$$watchers.forEach(function(watcher) {
            var oldValue = watcher.oldValue;
            var newValue = watcher.watcherFn();

            if (newValue !== oldValue)
                watcher.listenerFn(newValue, oldValue);

            watcher.oldValue = newValue;
        });
    };

    self.$apply = function(fn) {
        try {
            fn();
        } finally {
            self.$digest();
        }
    };
}

var $$directives = {
    'ng-bind': function(element, $scope) {
        var binding = element.attributes['ng-bind'].value;

        $scope.$watch(function() {
            return $scope[binding];
        }, function(newValue) {
            element.innerHTML = newValue;
        });
    },
    'ng-model': function(element, $scope) {
        var binding = element.attributes['ng-model'].value;

        $scope.$watch(function() {
            return $scope[binding];
        }, function(newValue) {
            if (element !== document.activeElement)
                element.value = newValue;
        });

        element.addEventListener('keyup', function() {
            $scope.$apply(function() {
                $scope[binding] = element.value;
            });
        });
    }
};

var $compile = function(element, $scope) {
    Array.prototype.forEach.call(element.children, function(child) {
        $compile(child, $scope);
    });

    Array.prototype.forEach.call(element.attributes, function(attr) {
        var directive = $$directives[attr.name];

        if (directive)
            directive(element, $scope);
    });
};

var $rootScope = new Scope();
$compile(document.body, $rootScope);

## index.html
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Hello Angular</title>
</head>
<body>
    <h1 ng-bind="message"></h1>
    <input type="text" ng-model="message"><br>
    <input type="text" ng-model="message">
    <p ng-bind="message"></p>

    <script type="text/javascript" src="angular.js"></script>
</body>
</html>
	function Scope() {
	var self = this;

	self.$$watchers = [];

	self.$watch = function(watcherFn, listenerFn) {
	self.$$watchers.push({
	watcherFn: watcherFn,
	listenerFn: listenerFn
	});
	};

	self.$digest = function() {
	self.$$watchers.forEach(function(watcher) {
	var oldValue = watcher.oldValue;
	var newValue = watcher.watcherFn();

	if (newValue !== oldValue)
	watcher.listenerFn(newValue, oldValue);

	watcher.oldValue = newValue;
	});
	};

	self.$apply = function(fn) {
	try {
	fn();
	} finally {
	self.$digest();
	}
	};
	}

	var $$directives = {
	'ng-bind': function(element, $scope) {
	var binding = element.attributes['ng-bind'].value;

	$scope.$watch(function() {
	return $scope[binding];
	}, function(newValue) {
	element.innerHTML = newValue;
	});
	},
	'ng-model': function(element, $scope) {
	var binding = element.attributes['ng-model'].value;

	$scope.$watch(function() {
	return $scope[binding];
	}, function(newValue) {
	if (element !== document.activeElement)
	element.value = newValue;
	});

	element.addEventListener('keyup', function() {
	$scope.$apply(function() {
	$scope[binding] = element.value;
	});
	});
	}
	};

	var $compile = function(element, $scope) {
	Array.prototype.forEach.call(element.children, function(child) {
	$compile(child, $scope);
	});

	Array.prototype.forEach.call(element.attributes, function(attr) {
	var directive = $$directives[attr.name];

	if (directive)
	directive(element, $scope);
	});
	};

	var $rootScope = new Scope();
	$compile(document.body, $rootScope);
	<!DOCTYPE html>
	<html lang="en">
	<head>
	<meta charset="UTF-8">
	<title>Hello Angular</title>
	</head>
	<body>
	<h1 ng-bind="message"></h1>
	<input type="text" ng-model="message"><br>
	<input type="text" ng-model="message">
	<p ng-bind="message"></p>

	<script type="text/javascript" src="angular.js"></script>
	</body>
	</html>