The isHTML() method of the TrustedTypePolicyFactory interface returns true if it is passed a valid TrustedHTML object.


The purpose of the functions isHTML(), isScript(), and isScriptURL() is to check if the object is a valid TrustedType object, created by a configured policy.


var isHTML = TrustedTypePolicyFactory.isHTML(value);


A TrustedHTML object.

Return value

A boolean that is true if the object is a valid TrustedHTML object.


In the below example the constant html was created by a policy, and therefore isHTML() returns true. The second example is an attempt to fake an object, and the third is a string. Both of these will return false when passed to isHTML().

const html = policy.createHTML('<div>');
console.log(trustedTypes.isHTML(html)) // true;

const fake = Object.create(TrustedHTML.prototype);
console.log(trustedTypes.isHTML(fake)); // false

console.log(trustedTypes.isHTML("<div>plain string</div>")); // false


Specification Status Comment
Trusted Types
The definition of 'TrustedTypePolicyFactory.isHTML()' in that specification.
Editor's Draft Initial definition.

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