angular1.x中雙向數據綁定指的是，HTML值變化，與其綁定的js中的變量值也變化，而這都主要依靠angular中$digest完成，無需過多的js代碼來實現
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<script src="angular.js"></script>
</head>
<body ng-app="ap" >
<div ng-controller="cl" >
<p>小框子1</p>
<input type="text" ng-model="input_value" />
<p>小框子2</p>
<input type="text" ng-model="input_value" />
</div>
</body>
<script>
var ap = angular.module("ap", [])
.controller("cl", function($scope){
$scope.input_value = "我是一個初值";
});
</script>
</html>