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

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


var isScript = TrustedTypePolicyFactory.isScript(value);



A TrustedScript object.

Return value

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


In the below example the constant url was created by a policy, and therefore isScriptURL() 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 isScriptURL().

const myScript = policy.createScript("eval('2 + 2')");
console.log(trustedTypes.isScript(myScript)) // true;

const fake = Object.create(TrustedScript.prototype);
console.log(trustedTypes.isScript(fake)); // false

console.log(trustedTypes.isScript("eval('2 + 2')")); // false


Trusted Types
# dom-trustedtypepolicyfactory-isscript

Browser compatibility

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