Block JavaScript optimizations on these sites

What it does

Allows you to set a list of site url patterns that specify sites for which advanced JavaScript optimizations are disabled. Disabling JavaScript optimizations will mean that Brave may render web content more slowly. For detailed information on valid url patterns, please see https://chromeenterprise.google/policies/url-patterns. Wildcards, *, are allowed. Policy exceptions can be set for specific subdomains as well as entire sites. For example, a policy set for only subdomain.site.com applies to subdomain.site.com without affecting site.com. In some cases where a subdomain cannot be isolated from its parent site, it may inherit the policy set on site.com. Exceptions may also not take effect for frames loaded in an existing tab until the site is opened in a new tab. On low-memory Android devices, site-specific exceptions may not be enforced, and sites will instead use the policy from DefaultJavaScriptOptimizerSetting, if set, or default to the profile's JavaScript optimization setting. To enforce exceptions, Brave may place sites or subdomains whose setting differs from the default into dedicated processes. This can increase memory usage, especially on Android or when a wildcard pattern matches many subdomains, since each matching origin may be isolated separately. Isolated subdomains also cannot use document.domain to access their parent site. Note: In versions 138 and earlier, policy exceptions were only enforced at a site granularity (eTLD+1). A policy set for only subdomain.site.com did not take effect, even for subdomain.site.com; it had to be set on site.com to apply to both site.com and subdomain.site.com. This policy applies on a frame-by-frame basis and not based on top level origin url alone, so e.g. if site-one.com is listed in the JavaScriptOptimizerBlockedForSites policy but site-one.com loads a frame containing site-two.com then site-one.com will have JavaScript optimizations disabled, but site-two.com will use the policy from DefaultJavaScriptOptimizerSetting, if set, or default to JavaScript optimizations enabled. Blocklist entries have higher priority than allowlist entries, which in turn have higher priority than the configured default value. If this policy is not set for a site then the policy from DefaultJavaScriptOptimizerSetting applies to the site, if set, otherwise JavaScript optimization is enabled for the site. Example value: [*.]example.edu

What it writes

Hive

HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER

Registry key

Software\Policies\BraveSoftware\Brave

Options

Configure and deploy

Choose a state and the option values; the output below is generated from the template for exactly that.

Windows Registry Editor Version 5.00

[-HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites]

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Block JavaScript optimizations on these sites
# Name: JavaScriptOptimizerBlockedForSites
# Scope: Machine
# State: Enabled
# Source: brave.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites'

./Device/Vendor/MSFT/Policy/Config/ADMX_brave/JavaScriptOptimizerBlockedForSites

$ErrorActionPreference = 'Stop'
$reasons = [System.Collections.Generic.List[string]]::new()

function Test-RegistryValueExists {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    return $null -ne (Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue)
}

function Test-RegistryValueEquals {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $Kind,
        [Parameter(Mandatory = $true)][object] $Expected
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return $false
    }

    $valueObject = Get-ItemProperty -LiteralPath $Path -Name $Name -ErrorAction SilentlyContinue
    if ($null -eq $valueObject) {
        return $false
    }

    $actual = $valueObject.$Name
    switch ($Kind) {
        'String' { return [string]$actual -ceq [string]$Expected }
        'ExpandString' { return [string]$actual -ceq [string]$Expected }
        'DWord' { return [uint32]$actual -eq [uint32]$Expected }
        'QWord' {
            $actualBits = if ($actual -is [uint64]) { $actual } else { [BitConverter]::ToUInt64([BitConverter]::GetBytes([int64]$actual), 0) }
            $expectedBits = if ($Expected -is [uint64]) { $Expected } else { [BitConverter]::ToUInt64([BitConverter]::GetBytes([int64]$Expected), 0) }
            return $actualBits -eq $expectedBits
        }
        'MultiString' {
            $actualArray = @($actual)
            $expectedArray = @($Expected)
            if ($actualArray.Count -ne $expectedArray.Count) { return $false }
            for ($index = 0; $index -lt $actualArray.Count; $index++) {
                if ([string]$actualArray[$index] -cne [string]$expectedArray[$index]) { return $false }
            }
            return $true
        }
        'Binary' {
            $actualArray = [byte[]]$actual
            $expectedArray = [byte[]]$Expected
            if ($actualArray.Length -ne $expectedArray.Length) { return $false }
            for ($index = 0; $index -lt $actualArray.Length; $index++) {
                if ($actualArray[$index] -ne $expectedArray[$index]) { return $false }
            }
            return $true
        }
        default { return [string]$actual -ceq [string]$Expected }
    }
}

# Policy: Block JavaScript optimizations on these sites
# Name: JavaScriptOptimizerBlockedForSites
# Scope: Machine
# State: Enabled
# Source: brave.admx

$keyPath = 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites'
if (Test-Path -LiteralPath $keyPath) {
    $propertyNames = (Get-Item -LiteralPath $keyPath).Property
    if ($propertyNames.Count -gt 0) {
        $reasons.Add('Key should be empty: HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites') | Out-Null
    }
}

if ($reasons.Count -eq 0) {
    Write-Output 'Compliant'
    exit 0
}

$reasons | ForEach-Object { Write-Output $_ }
exit 1

$ErrorActionPreference = 'Stop'

function Set-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name,
        [Parameter(Mandatory = $true)][string] $PropertyType,
        [Parameter(Mandatory = $true)][object] $Value
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        New-Item -Path $Path -Force | Out-Null
    }

    New-ItemProperty -LiteralPath $Path -Name $Name -PropertyType $PropertyType -Value $Value -Force | Out-Null
}

function Remove-RegistryValue {
    param(
        [Parameter(Mandatory = $true)][string] $Path,
        [Parameter(Mandatory = $true)][string] $Name
    )

    if (Test-Path -LiteralPath $Path) {
        Remove-ItemProperty -LiteralPath $Path -Name $Name -Force -ErrorAction SilentlyContinue
    }
}

function Clear-RegistryKeyValues {
    param(
        [Parameter(Mandatory = $true)][string] $Path
    )

    if (-not (Test-Path -LiteralPath $Path)) {
        return
    }

    foreach ($propertyName in (Get-Item -LiteralPath $Path).Property) {
        Remove-ItemProperty -LiteralPath $Path -Name $propertyName -Force -ErrorAction SilentlyContinue
    }
}

# Policy: Block JavaScript optimizations on these sites
# Name: JavaScriptOptimizerBlockedForSites
# Scope: Machine
# State: Enabled
# Source: brave.admx

Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites'

History 49 retained releases

1. 1.98.6021 Oct 2026
   Registry key: Software\Policies\BraveSoftware\Brave · Value name: Not specified
   • Description … information on valid url patterns, plea…[removed: JavaScript optimization policy exceptions…][added: Policy exceptions can be set for specific…] policy set for only subdomain.site.com [added: applies to subdomain.site.com without affe…]will [removed: not correctly apply][added: instead use the policy from DefaultJavaScriptOpti…] to [removed: site.com][added: the profile's JavaScript optimization setting. To enforce exceptio…] or [removed: subdomain.site.com][added: when a wildcard pattern matches many subdomains,] since …
     Whole description, marked

     Allows you to set a list of site url patterns that specify sites for which advanced JavaScript optimizations are disabled. Disabling JavaScript optimizations will mean that Brave may render web content more slowly. For detailed information on valid url patterns, please see https://chromeenterprise.google/policies/url-patterns. Wildcards, *, are allowed. [removed: JavaScript optimization policy exceptions will only be enforced at a site granularity (eTLD+1). A][added: Policy exceptions can be set for specific subdomains as well as entire sites. For example, a] policy set for only subdomain.site.com [added: applies to subdomain.site.com without affecting site.com. In some cases where a subdomain cannot be isolated from its parent site, it may inherit the policy set on site.com. Exceptions may also not take effect for frames loaded in an existing tab until the site is opened in a new tab. On low-memory Android devices, site-specific exceptions may not be enforced, and sites ]will [removed: not correctly apply][added: instead use the policy from DefaultJavaScriptOptimizerSetting, if set, or default] to [removed: site.com][added: the profile's JavaScript optimization setting. To enforce exceptions, Brave may place sites or subdomains whose setting differs from the default into dedicated processes. This can increase memory usage, especially on Android] or [removed: subdomain.site.com][added: when a wildcard pattern matches many subdomains,] since [removed: they both resolve to the same eTLD+1 (site.com) for which there is no policy.][added: each matching origin may be isolated separately. Isolated subdomains also cannot use document.domain to access their parent site. Note:] In [removed: this case,][added: versions 138 and earlier, policy exceptions were only enforced at a site granularity (eTLD+1). A] policy[removed: must][added: set for only subdomain.site.com did not take effect, even for subdomain.site.com; it had to] be set on site.com to[removed: ][added: ]apply [removed: correctly for ][added: to ]both site.com and[removed: ][added: ]subdomain.site.com. This policy applies on a frame-by-frame basis and not based on top level origin url alone, so e.g. if site-one.com is listed in the JavaScriptOptimizerBlockedForSites policy but site-one.com loads a frame containing site-two.com then site-one.com will have JavaScript optimizations disabled, but site-two.com will use the policy from DefaultJavaScriptOptimizerSetting, if set, or default to JavaScript optimizations enabled. Blocklist entries have higher priority than allowlist entries, which in turn have higher priority than the configured default value. If this policy is not set for a site then the policy from DefaultJavaScriptOptimizerSetting applies to the site, if set, otherwise JavaScript optimization is enabled for the site. Example value: [*.]example.edu

2. 1.88.13214 Mar 2026
   • Already present in the first release ChangeIntel keeps.

47 later releases left it unchanged.

Template

Internal name

JavaScriptOptimizerBlockedForSites

Namespace

BraveSoftware.Policies.Brave

Template file

brave.admx

Release

Brave Browser 1.99.56 · file set 81128c9e2b3d3d31…

<policy class="Both" displayName="$(string.JavaScriptOptimizerBlockedForSites)" explainText="$(string.JavaScriptOptimizerBlockedForSites_Explain)" key="Software\Policies\BraveSoftware\Brave" name="JavaScriptOptimizerBlockedForSites" presentation="$(presentation.JavaScriptOptimizerBlockedForSites)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="BraveSoftware.Policies.Brave:ContentSettings" />
      <supportedOn ref="BraveSoftware.Policies.Brave:SUPPORTED_WIN7" />
      <elements>
        <list id="JavaScriptOptimizerBlockedForSitesDesc" key="Software\Policies\BraveSoftware\Brave\JavaScriptOptimizerBlockedForSites" valuePrefix="" />
      </elements>
    </policy>

<presentation id="JavaScriptOptimizerBlockedForSites" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><listBox refId="JavaScriptOptimizerBlockedForSitesDesc">Block JavaScript optimizations on these sites</listBox></presentation>

BraveSoftware.Policies.Brave:category:Cat_Brave
<category displayName="$(string.Cat_Brave)" name="Cat_Brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
BraveSoftware.Policies.Brave:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="BraveSoftware.Policies.Brave:brave" />
    </category>
BraveSoftware.Policies.Brave:category:brave
<category displayName="$(string.brave)" name="brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="BraveSoftware.Policies.Brave:Cat_Brave" />
    </category>
BraveSoftware.Policies.Brave:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
BraveSoftware.Policies.Brave:category:Cat_Brave
<category displayName="$(string.Cat_Brave)" name="Cat_Brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="BraveSoftware.Policies.Brave:Cat_Brave">Brave Software</string></strings>
BraveSoftware.Policies.Brave:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="BraveSoftware.Policies.Brave:brave" />
    </category>
<strings><string id="BraveSoftware.Policies.Brave:ContentSettings_group">Content settings</string></strings>
BraveSoftware.Policies.Brave:category:brave
<category displayName="$(string.brave)" name="brave" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
      <parentCategory ref="BraveSoftware.Policies.Brave:Cat_Brave" />
    </category>
<strings><string id="BraveSoftware.Policies.Brave:brave">Brave</string></strings>
BraveSoftware.Policies.Brave:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="BraveSoftware.Policies.Brave:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>