I created a countdown function, but why isn't it producing any results?

Question

I created a countdown function, but why isn't it producing any results?

Hey there! Below is my HTML code where I'm trying to implement a countdown function using AngularJS.

var app = angular.module('myCountDown', []);

app.controller("Countdown",function($scope){

$scope.start = function(){
var temp = $scope.inputValue;

setInterval(function(){
if(temp<1){
return ;
}
temp -= 1;
$scope.count = temp;
console.log($scope.count);
},1000);
}
})

    <!doctype html>
<html lang="en">
<head>
<meta charset="UTF-8>
<title>Document</title>
</head>
<body ng-app="myCountDown">
<div ng-controller="Countdown">
<input type="text" ng-model="inputValue">
<button ng-click="start()">Start</button>
<input type="text" ng-model="count">
</div>
<script src="angular.min.js"></script>
<script src="app.js"></script>
<

I have the result displaying in the console, but it's not showing on the webpage for some reason.

Thank you!

javascript angularjs

Answer 1

Answer №1

Opt for $scope.$apply() to instantly view your updates OR utilize $interval as the preferred method in Angular over setTimeout.

DEMO

var app = angular.module('myCountDown', []);
app.controller("Countdown", function($scope, $interval) {
  $scope.start = function() {
    var temp = $scope.inputValue;
    $interval(function() {
      if (temp < 1) {
        return;
      }
      temp -= 1;
      $scope.count = temp;
      console.log($scope.count);
    }, 1000);
  }
})

<!doctype html>
<html lang="en>
 <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<head>
<meta charset="UTF-8>
<title>Document</title>
</head>
<body ng-app="myCountDown">
<div ng-controller="Countdown">
  <h1> {{count}}</h1>
<input type="text" ng-model="inputValue">
<button ng-click="start()">Begin</button>
    {{count}}
<input type="text" ng-model="count">
</div>

</body>
</html>

Answer 2

Opt for $scope.$apply() to instantly view your updates OR utilize $interval as the preferred method in Angular over setTimeout.

DEMO

var app = angular.module('myCountDown', []);
app.controller("Countdown", function($scope, $interval) {
  $scope.start = function() {
    var temp = $scope.inputValue;
    $interval(function() {
      if (temp < 1) {
        return;
      }
      temp -= 1;
      $scope.count = temp;
      console.log($scope.count);
    }, 1000);
  }
})

<!doctype html>
<html lang="en>
 <script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.4.8/angular.min.js"></script>
<head>
<meta charset="UTF-8>
<title>Document</title>
</head>
<body ng-app="myCountDown">
<div ng-controller="Countdown">
  <h1> {{count}}</h1>
<input type="text" ng-model="inputValue">
<button ng-click="start()">Begin</button>
    {{count}}
<input type="text" ng-model="count">
</div>

</body>
</html>

Answer 3

Answer №2

setInterval will be executed outside of angular's scope. To handle this within Angular, use $interval instead. It is important to clear the previous interval before creating a new one.

See the example below for reference.

var app = angular.module('myCountDown', []);

app.controller("Countdown", function($scope, $interval) {

  $scope.start = function() {
    var temp = $scope.inputValue;
    if ($scope.sampleInterval) {
      $interval.cancel($scope.sampleInterval);
    }
    $scope.sampleInterval = $interval(function() {
      if (temp < 1) {
        return;
      }
      temp -= 1;
      $scope.count = temp;
      console.log($scope.count);
    }, 1000);
  }
})

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<div ng-app="myCountDown">
  <div ng-controller="Countdown">
    <input type="text" ng-model="inputValue">
    <button ng-click="start()">Start</button>
    <input type="text" ng-model="count">
  </div>
  <script src="angular.min.js"></script>
  <script src="app.js"></script>
</div>

Answer 4

setInterval will be executed outside of angular's scope. To handle this within Angular, use $interval instead. It is important to clear the previous interval before creating a new one.

See the example below for reference.

var app = angular.module('myCountDown', []);

app.controller("Countdown", function($scope, $interval) {

  $scope.start = function() {
    var temp = $scope.inputValue;
    if ($scope.sampleInterval) {
      $interval.cancel($scope.sampleInterval);
    }
    $scope.sampleInterval = $interval(function() {
      if (temp < 1) {
        return;
      }
      temp -= 1;
      $scope.count = temp;
      console.log($scope.count);
    }, 1000);
  }
})

<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.6.4/angular.min.js"></script>
<div ng-app="myCountDown">
  <div ng-controller="Countdown">
    <input type="text" ng-model="inputValue">
    <button ng-click="start()">Start</button>
    <input type="text" ng-model="count">
  </div>
  <script src="angular.min.js"></script>
  <script src="app.js"></script>
</div>

Answer 5

Answer №3

To address this issue, I have a solution in mind that involves making modifications to the JavaScript file.

var app = angular.module('myCountDown', []);

app.controller("Countdown",function($scope){

$scope.start = function(){
var temp = $scope.inputValue;

setInterval(function(){
if(temp<1){
return ;
}
temp -= 1;
$scope.count = temp;
$scope.$apply();
console.log($scope.count);
},1000);
}
})

In order to activate the Angular application manually, we must remember to use $scope.$apply();

Answer 6

To address this issue, I have a solution in mind that involves making modifications to the JavaScript file.

var app = angular.module('myCountDown', []);

app.controller("Countdown",function($scope){

$scope.start = function(){
var temp = $scope.inputValue;

setInterval(function(){
if(temp<1){
return ;
}
temp -= 1;
$scope.count = temp;
$scope.$apply();
console.log($scope.count);
},1000);
}
})

In order to activate the Angular application manually, we must remember to use $scope.$apply();

I created a countdown function, but why isn't it producing any results?

Answer №1

Answer №2

Answer №3

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