Execute the function only if the checkbox has been selected

Question

Execute the function only if the checkbox has been selected

Just starting out with angular.js and I wanted to create an html list with checkboxes. My goal was to trigger a javascript function when a user checks a checkbox.

<input id='box' ng-model='" + key + "'  ng-change='graphquery(\"" + key + "\")' class = 'queryNameList css-checkbox' type = 'checkbox' />

Here, I've used the ng-change directive which captures all changes and calls the graphquery function regardless of whether the checkbox is checked or unchecked.

Is there a way to specify a condition so that the function is only called when the checkbox is checked?

javascript angularjs

Answer 1

Answer №1

ng-change="!selected || updateData(selected)"

When the checkbox is selected, !selected becomes false, triggering the execution of updateData(selected).

If the checkbox is deselected, !selected becomes true, causing anything after || to be disregarded;

Answer 2

ng-change="!selected || updateData(selected)"

When the checkbox is selected, !selected becomes false, triggering the execution of updateData(selected).

If the checkbox is deselected, !selected becomes true, causing anything after || to be disregarded;

Answer 3

Answer №2

$scope.dataHandler = function(data){
  if(!$scope[data]){
   //no action required
   return;
  }

//process data accordingly
}

Answer 4

$scope.dataHandler = function(data){
  if(!$scope[data]){
   //no action required
   return;
  }

//process data accordingly
}

Answer 5

Answer №3

Take a look at this sample from the official documentation.

When using ngModel on a checkbox, it will be either true or

false>, which is then passed to the specified function in <code>ngChange

. To define specific truth and falseness values, utilize the ngTrueValue and ngFalseValue directives.

For a live demonstration, view this Plunk.

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

app.controller('MainCtrl',
  function($scope) {

    $scope.graphQuery = function(key) {
      if (key)
        $scope.key = key
    }

    $scope.returnKey = function() {
      return '123'
    }
  }
)

Below is the HTML code:

<body ng-controller="MainCtrl">
    <input id='box' ng-model='key' ng-change='graphQuery()' class='queryNameList css-checkbox'
       type='checkbox' ng-true-value="{{returnKey()}}" />

    <pre>Key: {{key}}</pre>
</body>

To ensure that your code only executes when the value of key is true, you can specify a custom function in ng-true-value to return a string in such cases.

Answer 6

Take a look at this sample from the official documentation.

When using ngModel on a checkbox, it will be either true or

false>, which is then passed to the specified function in <code>ngChange

. To define specific truth and falseness values, utilize the ngTrueValue and ngFalseValue directives.

For a live demonstration, view this Plunk.

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

app.controller('MainCtrl',
  function($scope) {

    $scope.graphQuery = function(key) {
      if (key)
        $scope.key = key
    }

    $scope.returnKey = function() {
      return '123'
    }
  }
)

Below is the HTML code:

<body ng-controller="MainCtrl">
    <input id='box' ng-model='key' ng-change='graphQuery()' class='queryNameList css-checkbox'
       type='checkbox' ng-true-value="{{returnKey()}}" />

    <pre>Key: {{key}}</pre>
</body>

To ensure that your code only executes when the value of key is true, you can specify a custom function in ng-true-value to return a string in such cases.

Answer 7

Answer №4

function triggerFunction() {
  document.getElementById('box').addEventListener('change', function(){ 
    if(this.checked === true) runMyFunction();
  });
}

Answer 8

function triggerFunction() {
  document.getElementById('box').addEventListener('change', function(){ 
    if(this.checked === true) runMyFunction();
  });
}

Execute the function only if the checkbox has been selected

Answer №1

Answer №2

Answer №3

Answer №4

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