You see this error when Angular detects an attribute binding or a property binding on an <iframe> element using the following property names:
- sandbox
- allow
- allowFullscreen
- referrerPolicy
- csp
- fetchPriority
The mentioned attributes affect the security model setup for <iframe>s
and it's important to apply them before setting the src or srcdoc attributes.
To enforce that, Angular requires these attributes to be set on <iframe>s as
static attributes, so the values are set at the element creation time and they
remain the same throughout the lifetime of an <iframe> instance.
The error is thrown when a property binding with one of the mentioned attribute names is used:
<iframe [sandbox]="'allow-scripts'" src="..."></iframe>
or when it's an attribute bindings:
<iframe [attr.sandbox]="'allow-scripts'" src="..."></iframe>
Also, the error is thrown when a similar pattern is used in Directive's host bindings:
@Directive({ selector: 'iframe', host: { '[sandbox]': `'allow-scripts'`, '[attr.sandbox]': `'allow-scripts'`, }})class IframeDirective {}
Debugging the error
The error message includes the name of the component with the template where
an <iframe> element with unsafe bindings is located.
The recommended solution is to use the mentioned attributes as static ones, for example:
<iframe sandbox="allow-scripts" src="..."></iframe>
If you need to have different values for these attributes (depending on various conditions),
you can use an *ngIf or an *ngSwitch on an <iframe> element:
<iframe *ngIf="someConditionA" sandbox="allow-scripts" src="..."></iframe><iframe *ngIf="someConditionB" sandbox="allow-forms" src="..."></iframe><iframe *ngIf="someConditionC" sandbox="allow-popups" src="..."></iframe>