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Copy file name to clipboardExpand all lines: files/en-us/web/api/document/parsehtmlunsafe_static/index.md
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@@ -50,9 +50,10 @@ A {{domxref("Document")}}.
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- : This is thrown if:
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-`html` is passed a string when [Trusted Types](/en-US/docs/Web/API/Trusted_Types_API) are [enforced by a CSP](/en-US/docs/Web/API/Trusted_Types_API#using_a_csp_to_enforce_trusted_types) and no default policy is defined.
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-`options.sanitizer` is passed a:
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-value that is not a {{domxref("Sanitizer")}}, {{domxref("SanitizerConfig")}}, or string.
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- non-normalized {{domxref("SanitizerConfig")}} (one that includes both "allowed" and "removed" configuration settings).
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- {{domxref("SanitizerConfig")}} that isn't [valid](/en-US/docs/Web/API/SanitizerConfig#valid_configuration).
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For example, a configuration that includes both "allowed" and "removed" configuration settings.
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- string that does not have the value `"default"`.
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- value that is not a {{domxref("Sanitizer")}}, {{domxref("SanitizerConfig")}}, or string.
Copy file name to clipboardExpand all lines: files/en-us/web/api/element/sethtmlunsafe/index.md
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@@ -50,9 +50,10 @@ None (`undefined`).
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- : This is thrown if:
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-`input` is passed a string when [Trusted Types](/en-US/docs/Web/API/Trusted_Types_API) are [enforced by a CSP](/en-US/docs/Web/API/Trusted_Types_API#using_a_csp_to_enforce_trusted_types) and no default policy is defined.
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-`options.sanitizer` is passed a:
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-value that is not a {{domxref("Sanitizer")}}, {{domxref("SanitizerConfig")}}, or string.
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- non-normalized {{domxref("SanitizerConfig")}} (one that includes both "allowed" and "removed" configuration settings).
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- {{domxref("SanitizerConfig")}} that isn't [valid](/en-US/docs/Web/API/SanitizerConfig#valid_configuration).
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For example, a configuration that includes both "allowed" and "removed" configuration settings.
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- string that does not have the value `"default"`.
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- value that is not a {{domxref("Sanitizer")}}, {{domxref("SanitizerConfig")}}, or string.
The other XSS-safe methods, {{domxref('ShadowRoot.setHTML()')}} and {{domxref('Document/parseHTML_static','Document.parseHTML()')}}, are used in the same way.
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### Safe methods further restrict allowed entities
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##Using a sanitizer configuration
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You can specify the HTML entities that you want to allow or remove by passing a {{domxref('Sanitizer')}} in the second argument of all the sanitizer methods.
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All of the sanitization methods can be passed a {{domxref('Sanitizer')}} or {{domxref('SanitizerConfig')}}, which defines what elements, attributes and comments are either allowed, or should be removed, when inserting strings of HTML.
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For example, if you know that only {{htmlelement("p")}} and {{htmlelement("a")}} elements are expected in the context of "someElement" below, you might create a sanitizer configuration that allows only those elements:
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The {{domxref('Sanitizer')}} is essentially a wrapper around a {{domxref('SanitizerConfig')}}, performing some optimizations and normalizations that make it easier and safer to use, share and modify,
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### Using safe methods with a sanitizer
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The XSS-safe methods always remove any unsafe HTML elements or attributes (as discussed in [Safe sanitization by default](#safe_sanitization_by_default) above).
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You can pass a sanitizer as the second argument to the safe methods to allow the same or fewer entities than the default configuration.
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For example, if you know that only {{htmlelement("p")}} and {{htmlelement("a")}} elements are expected in the context of `someElement` below, you might create a sanitizer configuration that allows only those elements:
Note though that the unsafe HTML entities are always removed when using the safe methods.
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When used with the safe methods, a permissive sanitizer configuration, will either allow the same or fewer entities than the default configuration.
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### Allowing unsafe sanitization
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## Allowing unsafe sanitization
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Sometimes you might want to inject input that needs to contain potentially unsafe elements or attributes.
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In this case you could use one of the API XSS-unsafe methods: {{domxref('Element.setHTMLUnsafe()')}}, {{domxref('ShadowRoot.setHTMLUnsafe()')}}, and {{domxref('Document/parseHTMLUnsafe_static','Document.parseHTMLUnsafe()')}}.
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Sometimes you might want to inject input needs to contain potentially unsafe elements or attributes.
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In this case you can use one of the API XSS-unsafe methods: {{domxref('Element.setHTMLUnsafe()')}}, {{domxref('ShadowRoot.setHTMLUnsafe()')}}, and {{domxref('Document/parseHTMLUnsafe_static','Document.parseHTMLUnsafe()')}}.
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A common approach is to start from the default sanitizer, which only allows safe elements, and then allow just those unsafe entities that we expect in the input.
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To somewhat reduce the risk, you might first construct the default sanitizer, which only allows XSS-safe elements, and then allow just those unsafe entities that are expected in the input.
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For example, in the following sanitizer all safe elements are allowed, and we further allow the unsafe `onclick` handler on `button` elements (only).
With this code the `alert(1)` would be allowed, and there is a potential issue that the attribute might be used for malicious purposes.
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However we know that all other XSS unsafe HTML entities have been removed, so we only need to worry about this one case, and can put in other mitigations.
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The unsafe methods will use any sanitizer configuration you supply (or none), so you need to be more careful than when using the safe methods.
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The unsafe methods will use any sanitizer configuration you supply (or none), so you need to be careful when using them.
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Minimally you should enforce [Trusted Types](/en-US/docs/Web/API/HTML_Sanitizer_API#sanitization_and_trusted_types) and pass {{domxref("TrustedHTML")}} instead of strings into the methods.
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## Allow configurations
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});
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```
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You can add the elements to the`Sanitizer` using its API.
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You can also add the elements to a`Sanitizer` using {{domxref("Sanitizer.allowElement()")}}.
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Here we add the same elements to an empty sanitizer:
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```js
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});
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```
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You can also add each of the allowed attributes to the`Sanitizer` using its `allowAttribute()` method:
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You can also add each of the allowed attributes to a`Sanitizer` using the {{domxref("Sanitizer.allowAttribute()")}} method:
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```js
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constsanitizer=newSanitizer({});
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In both cases you can also specify each attribute as an object with `name` and `namespace` properties.
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You can also use set the attribute properties using the same element object passed to {{domxref("Sanitizer.allowElement()")}}.
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Note however that you can't specify both element `attributes` and `removeAttributes` in one call. Attempting to do so will raise an exception.
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Note that it is impossible to define per-element attribute behavior on a Sanitizer with a remove configuration, as the (needed) `elements` array is not present.
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Other restrictions on per-element attributes are covered in [Valid configurations](/en-US/docs/Web/API/SanitizerConfig#valid_configuration)
The {{domxref("SanitizerConfig")}} can also be used to specify whether comments and `data-` attributes will be filtered from injected content, using the [comments](/en-US/docs/Web/API/SanitizerConfig#comments) and [dataAttributes](/en-US/docs/Web/API/SanitizerConfig#dataattributes) boolean properties, respectively.
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The {{domxref("SanitizerConfig")}} can also be used to specify whether comments will be filtered from injected content, using the [`comments`](/en-US/docs/Web/API/SanitizerConfig#comments)property, and whether `data-` attributes are allowed without having to add them to the `attributes` array using the [`dataAttributes`](/en-US/docs/Web/API/SanitizerConfig#dataattributes) boolean property.
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To allow both comments and data attributes you might use a configuration like this:
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To allow comments and all `data-*` attributes you might use a configuration like this:
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```js
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constsanitizer=newSanitizer({
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});
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```
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You can similarly enable or disable the comments or data-attributes on an existing sanitizer using {{domxref("Sanitizer.setComments()")}} and {{domxref("Sanitizer.setDataAttributes()")}} methods:
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You can similarly set the comments or data-attributes properties on an existing sanitizer using {{domxref("Sanitizer.setComments()")}} and {{domxref("Sanitizer.setDataAttributes()")}}:
All the sanitization methods can be passed a sanitizer configuration that is either a {{domxref("Sanitizer")}} or {{domxref("SanitizerConfig")}} instance.
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The {{domxref("SanitizerConfig")}} provides a compact method for specifying multiple elements or attributes that should be allowed or removed at the same time.
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Some care may be required when modifying this object to ensure that it remains a [valid configuration](/en-US/docs/Web/API/SanitizerConfig#valid_configuration).
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The {{domxref("Sanitizer")}} object is a wrapper around {{domxref("SanitizerConfig")}} that provides additional useful functionality:
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- The default constructor creates a configuration that allows all XSS-safe elements and attributes, and which is therefore a good starting point for creating either slightly more or slightly less restrictive sanitizers.
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- When you use the methods to allow or remove HTML entities, the entities are removed from the "opposite" lists.
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These normalizations make the configuration more efficient.
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- The `Sanitizer` methods ensure that the underlying `SanitizerConfig` remains a [valid configuration](/en-US/docs/Web/API/SanitizerConfig#valid_configuration).
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For example, if you call `allowElement()` to allow an element then the element would also be removed from the underlying `replaceWithChildrenElements` array (if present).
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The normalizations make the configuration more efficient.
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- The {{domxref("Sanitizer.removeUnsafe()")}} method can be used to remove all XSS-unsafe entities from an existing configuration.
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- You can export the configuration to see exactly what entities are allowed and dropped.
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Note though, if you can use the safe sanitization methods, then you may not need to define a sanitizer configuration at all.
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Note that if you can use the safe sanitization methods, then you may not need to define a sanitizer configuration at all.
The **`allowAttribute()`** method of the {{domxref("Sanitizer")}} interface sets an attribute to be allowed on all elements.
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The **`allowAttribute()`** method of the {{domxref("Sanitizer")}} interface sets an attribute to be allowed on all elements when the sanitizer is used.
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The specified attribute is added to the list of [`attributes`](/en-US/docs/Web/API/SanitizerConfig#attributes_2) in this sanitizer's configuration.
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The attribute is removed from the [`removeAttributes`](/en-US/docs/Web/API/SanitizerConfig#removeattributes_2) list if present.
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The method can be used with either an [allow configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#allow_configurations) or a [remove configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#remove_configurations).
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If used with an allow configuration, the specified attribute is added to the `attributes` array.
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If used with a remove configuration, the attribute is removed from the `removeAttributes` array (if present).
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Note that to allow/disallow attributes only on specific elements use {{domxref('Sanitizer.allowElement()')}}.
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### Return value
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None (`undefined`).
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`true` if the operation changed the configuration to allow the attribute, and `false` if the configuration already allowed the attribute.
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Note that `false` might be returned if the internal configuration:
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- defines an [`attributes`](/en-US/docs/Web/API/SanitizerConfig#attributes) array and the attribute is already present (it does not need to be added again)
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- instead defines the [`removeAttributes`](/en-US/docs/Web/API/SanitizerConfig#removeattributes) array and the specified attribute is not present (and is hence already allowed)
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-[`dataAttributes`](/en-US/docs/Web/API/SanitizerConfig#dataattributes) is set `true`, but a `data-*` attribute is passed.
The **`allowElement()`** method of the {{domxref("Sanitizer")}} interface sets that the specified element is allowed in the output when the sanitizer is used.
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The element can be specified with lists of attributes that are allowed or disallowed on elements of that type.
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The specified element is added to the [`elements`](/en-US/docs/Web/API/SanitizerConfig#elements) list in this sanitizer's configuration.
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If the element is already present in the list, then the existing entry is first removed and the new definition is appended to the end of the list.
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Note that if you need both per-element add-attribute and remove-attribute lists, they must be added in a single call to this method (since if done in two calls, the second call will replace the element definition added in the first call).
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The specified element is removed from the sanitizer configuration [`removeElements`](/en-US/docs/Web/API/SanitizerConfig#removeelements) or [`replaceWithChildrenElements`](/en-US/docs/Web/API/SanitizerConfig#replacewithchildrenelements) lists if present.
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It can also be used to specify per-element attribute allow or remove arrays on `Sanitizer` instances with an [allow configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#allow_configurations).
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## Syntax
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### Return value
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None (`undefined`).
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`true` if the operation changed the configuration to allow the element, and `false` if the configuration was not changed (usually because the element was already allowed, but potentially because the change could not be made).
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Note that `false` might be returned if the internal configuration:
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- defines the [`elements`](/en-US/docs/Web/API/SanitizerConfig#elements) array and the element is already present (it does not need to be added again).
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- defines the [`removeElements`](/en-US/docs/Web/API/SanitizerConfig#removeelements) array and the specified element is not present (and is hence already not filtered).
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- defines the [`removeElements`](/en-US/docs/Web/API/SanitizerConfig#removeelements) array and attempts to allow an element with per-element attributes.
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This operation is not supported because in a [valid configuration](/en-US/docs/Web/API/SanitizerConfig#valid_configuration) you can't have both `removeElements` and `elements` arrays, and per-element attributes are added in the `elements` array.
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The call won't change the configuration and will generate a console warning.
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## Description
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The `allowElement()` method sets that the specified element is allowed in the output when the sanitizer is used.
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The method can be used with either an [allow configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#allow_configurations) or a [remove configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#remove_configurations).
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If used with an allow configuration, the specified element is added to the `elements` array.
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If used with a remove configuration, the element is removed from the `removeElements` array (if present).
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If present, it would also be removed from the [`replaceWithChildrenElements`](/en-US/docs/Web/API/SanitizerConfig#replacewithchildrenelements) array.
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For example, the following code creates an allow `Sanitizer` that allows {{htmlelement("span")}} elements and then calls `allowElement()` to additionally allow {{htmlelement("b")}} elements.
When using a `Sanitizer` with an allow configuration you can also use the method to specify attributes to be allowed or disallowed on elements of that type.
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For example, the following code first creates an allow sanitizer configuration by specifying the `elements` array (creating a `Sanitizer` with an empty object or no configuration object would also result in an "allow configuration").
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It then calls `allowElement()` to allow `div` elements, to allow the `class` attribute on `<div>` elements, and to remove the `lang` attribute on `<div>` elements.
If you need both per-element add-attribute and remove-attribute arrays as shown above, they must be added in a single call to this method.
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If you were to do this in two calls the the second call would replace the element definition added in the first call.
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When using a `Sanitizer` with a [remove configuration](/en-US/docs/Web/API/HTML_Sanitizer_API#remove_configurations), similar code to add per-element attribute allow or remove arrays will generate a console warning and return `false`.
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This is because internally the sanitizer doesn't have the `elements` array required to specify per-element attributes and won't change the configuration.
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```js example-bad
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// Define Sanitizer with a remove configuration
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// by specifying removeElements in the configuration
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