The ng-disabled directive in AngularJS remains disabled even after the condition is no longer

Question

The ng-disabled directive in AngularJS remains disabled even after the condition is no longer

When utilizing

ng-disabled="truthy_scope_variable"

to conditionally disable a text input field in AngularJS, an unexpected behavior occurs. The field is disabled the first time the scope variable is turned from truthy to falsified, but subsequent changes do not enable it as expected. Despite monitoring the variable's change with $watch and trying to trigger updates with $apply, the input field remains disabled without any errors logged in the Console.

The scope variable in question is linked to a radio button model, where setting $scope.new_account = true should enable the input field, but this does not happen as intended. It seems that AngularJS may be overlooking DOM changes or failing to register the modifications properly.

Code snippet from controller:

$scope.new_account = true

Radio buttons binding:

<input type="radio" ng-model="new_account" name="register"
 id="radio_new_account" value="true" />

<input type="radio" ng-model="new_account" name="register"
 id="radio_existing_account" value="false" />

Text input field with conditional disabling:

<input type="password" ng-disabled="new_account" id="login-password"
 name="password" ng-model="password" />

Even if initially set to false, rendering the field disabled, the issue persists where it fails to re-enable upon changing the scope variable. The root cause of this behavior remains unclear.

javascript angularjs angularjs-scope

Answer 1

Answer №1

One reason for this is that HTML attributes are always treated as strings. In your scenario, ngDisabled interprets the values as "true" or "false", which are both strings.

To resolve this issue, you should compare the model against the string value in ngDisabled:

ng-disabled="new_account == 'false'"

... alternatively, you can use a checkbox to obtain the actual boolean value:

<input type="checkbox" ng-model="existing_account" name="register" id="checkbox_new_account" />
<label for="checkbox_new_account">Is Existing Account</label>

Password:
<input type="password" ng-disabled="existing_account" name="password" ng-model="password" />

For a demonstration, refer to this PLNKR link containing both solutions.

Answer 2

One reason for this is that HTML attributes are always treated as strings. In your scenario, ngDisabled interprets the values as "true" or "false", which are both strings.

To resolve this issue, you should compare the model against the string value in ngDisabled:

ng-disabled="new_account == 'false'"

... alternatively, you can use a checkbox to obtain the actual boolean value:

<input type="checkbox" ng-model="existing_account" name="register" id="checkbox_new_account" />
<label for="checkbox_new_account">Is Existing Account</label>

Password:
<input type="password" ng-disabled="existing_account" name="password" ng-model="password" />

For a demonstration, refer to this PLNKR link containing both solutions.

Answer 3

Answer №2

If you're looking for another solution, consider using

ng-value

 <input type="radio" ng-model="new_account" name="register"
 id="radio_new_account" ng-value="true" />

<input type="radio" ng-model="new_account" name="register"
 id="radio_existing_account" ng-value="false" />
      <input type="password" ng-disabled="new_account" id="login-password"
 name="password" ng-model="password" />

Answer 4

If you're looking for another solution, consider using

ng-value

 <input type="radio" ng-model="new_account" name="register"
 id="radio_new_account" ng-value="true" />

<input type="radio" ng-model="new_account" name="register"
 id="radio_existing_account" ng-value="false" />
      <input type="password" ng-disabled="new_account" id="login-password"
 name="password" ng-model="password" />

Answer 5

Answer №3

Starting in 2016, it was noticed that the bound values would refresh the user interface on Chrome and Firefox even when the ng-disabled condition is true, but this behavior does not occur on Safari. In Safari, the UI remains unchanged when using ng-disabled, although the input element's value property shows the updated value (verify with element.value after modification).

To ensure UI updates in Safari while utilizing ng-model or ng-value directives, it is recommended to use ng-readonly instead of ng-disabled.

Answer 6

Starting in 2016, it was noticed that the bound values would refresh the user interface on Chrome and Firefox even when the ng-disabled condition is true, but this behavior does not occur on Safari. In Safari, the UI remains unchanged when using ng-disabled, although the input element's value property shows the updated value (verify with element.value after modification).

To ensure UI updates in Safari while utilizing ng-model or ng-value directives, it is recommended to use ng-readonly instead of ng-disabled.

The ng-disabled directive in AngularJS remains disabled even after the condition is no longer

Code snippet from controller:

Radio buttons binding:

Text input field with conditional disabling:

Answer №1

Answer №2

Answer №3

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