Google › Google Chrome › Content settings
Block JavaScript optimizations on these sites
Supported on Microsoft Windows 7 or later
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 Google Chrome may render web content more slowly. For detailed information on valid url patterns, please see https://chromeenterprise.google/policies/url-patterns. Wildcards, *, are allowed. JavaScript optimization policy exceptions will only be enforced at a site granularity (eTLD+1). A policy set for only subdomain.site.com will not correctly apply to site.com or subdomain.site.com since they both resolve to the same eTLD+1 (site.com) for which there is no policy. In this case, policy must be set on site.com to apply correctly for 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\Google\Chrome
Options
| Option | Type | Registry value | Allowed values |
|---|---|---|---|
| Block JavaScript optimizations on these sites | List of values | Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites |
Any |
Configure and deploy
Choose a state and the option values; the output below is generated from the template for exactly that.
Enabled · Computer · template defaults
Registry file (.reg)
Windows Registry Editor Version 5.00
[-HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites]
PowerShell
$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: chrome.admx
Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites'
- The OMA-URI is an inferred ADMX-backed Policy CSP candidate derived from the source ADMX file name and policy name.
- Some Microsoft policies use built-in Policy CSP pages whose area names don't match the ADMX file name, so verify the candidate against Microsoft Learn before deployment.
- The generated payload is incomplete because one or more ADMX element values were not supplied: JavaScriptOptimizerBlockedForSitesDesc
ADMX profile candidate (OMA-URI)
./Device/Vendor/MSFT/Policy/Config/ADMX_chrome/JavaScriptOptimizerBlockedForSitesIntune remediation scripts
Detection
$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]$Expected }
'QWord' { return [uint64]$actual -eq [uint64]$Expected }
'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: chrome.admx
$keyPath = 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites'
if (Test-Path -LiteralPath $keyPath) {
$propertyNames = (Get-Item -LiteralPath $keyPath).Property
if ($propertyNames.Count -gt 0) {
$reasons.Add('Key should be empty: HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites') | Out-Null
}
}
if ($reasons.Count -eq 0) {
Write-Output 'Compliant'
exit 0
}
$reasons | ForEach-Object { Write-Output $_ }
exit 1
Remediation
$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 $propertyName -Force -ErrorAction SilentlyContinue
}
}
# Policy: Block JavaScript optimizations on these sites
# Name: JavaScriptOptimizerBlockedForSites
# Scope: Machine
# State: Enabled
# Source: chrome.admx
Clear-RegistryKeyValues -Path 'Registry::HKEY_LOCAL_MACHINE\Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites'
History 1 retained release
- 155.0.8059.8519 Oct 2026
- Already present in the first release ChangeIntel keeps.
Template
- Internal name
JavaScriptOptimizerBlockedForSites- Namespace
Google.Policies.Chrome- Template file
chrome.admx- Release
- Google Chrome 155.0.8059.85 · file set
1f03ffd12695d620…
Definition, editor controls and support
Definition
<policy class="Both" displayName="$(string.JavaScriptOptimizerBlockedForSites)" explainText="$(string.JavaScriptOptimizerBlockedForSites_Explain)" key="Software\Policies\Google\Chrome" name="JavaScriptOptimizerBlockedForSites" presentation="$(presentation.JavaScriptOptimizerBlockedForSites)" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Google.Policies.Chrome:ContentSettings" />
<supportedOn ref="Google.Policies.Chrome:SUPPORTED_WIN7" />
<elements>
<list id="JavaScriptOptimizerBlockedForSitesDesc" key="Software\Policies\Google\Chrome\JavaScriptOptimizerBlockedForSites" valuePrefix="" />
</elements>
</policy>Editor controls
<presentation id="JavaScriptOptimizerBlockedForSites" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions"><listBox refId="JavaScriptOptimizerBlockedForSitesDesc">Block JavaScript optimizations on these sites</listBox></presentation>Supported platforms and category
Google.Policies.Chrome:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Google.Policies.Chrome:googlechrome" />
</category>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Google.Policies:Cat_Google" />
</category>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
Google.Policies.Chrome:category:ContentSettings
<category displayName="$(string.ContentSettings_group)" name="ContentSettings" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Google.Policies.Chrome:googlechrome" />
</category>
<strings><string id="Google.Policies.Chrome:ContentSettings_group">Content settings</string></strings>
Google.Policies.Chrome:category:googlechrome
<category displayName="$(string.googlechrome)" name="googlechrome" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions">
<parentCategory ref="Google.Policies:Cat_Google" />
</category>
<strings><string id="Google.Policies.Chrome:googlechrome">Google Chrome</string></strings>
Google.Policies.Chrome:definition:SUPPORTED_WIN7
<definition displayName="$(string.SUPPORTED_WIN7)" name="SUPPORTED_WIN7" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies.Chrome:SUPPORTED_WIN7">Microsoft Windows 7 or later</string></strings>
Google.Policies:category:Cat_Google
<category displayName="$(string.google)" name="Cat_Google" xmlns="http://schemas.microsoft.com/GroupPolicy/2006/07/PolicyDefinitions" />
<strings><string id="Google.Policies:google">Google</string></strings>