diff --git a/js/web/karma.conf.js b/js/web/karma.conf.js
index 9e44d9c0d9652..507da0de2b4ad 100644
--- a/js/web/karma.conf.js
+++ b/js/web/karma.conf.js
@@ -9,6 +9,8 @@ const karmaPlugins = args['karma-plugins'] || undefined;
 const timeoutMocha = args['timeout-mocha'] || 60000;
 const forceLocalHost = !!args['force-localhost'];
 
+// user data directory; will be passed to the Edge/Chrome/ChromeCanary/Firefox launchers
+const userDataDir = args['user-data-dir'];
 // parse chromium flags
 let chromiumFlags = args['chromium-flags'];
 if (!chromiumFlags) {
@@ -87,9 +89,10 @@ module.exports = function(config) {
     listenAddress,
     customLaunchers: {
       // Chromium-based browsers
-      EdgeTest: {base: 'Edge', flags: chromiumFlags},
-      ChromeTest: {base: 'Chrome', flags: chromiumFlags},
-      ChromeCanaryTest: {base: 'ChromeCanary', flags: chromiumFlags},
+      EdgeTest: {base: 'Edge', flags: chromiumFlags, edgeDataDir: userDataDir},
+      ChromeTest: {base: 'Chrome', flags: chromiumFlags, chromeDataDir: userDataDir},
+      ChromeCanaryTest: {base: 'ChromeCanary', flags: chromiumFlags, chromeDataDir: userDataDir},
+      FirefoxTest: {base: 'Firefox', profile: userDataDir},
 
       //
       // ==== BrowserStack browsers ====
diff --git a/js/web/script/test-runner-cli-args.ts b/js/web/script/test-runner-cli-args.ts
index b2b212bdb9bc1..745f504b0494d 100644
--- a/js/web/script/test-runner-cli-args.ts
+++ b/js/web/script/test-runner-cli-args.ts
@@ -103,6 +103,7 @@ Options:
 
  --no-sandbox                  This flag will be passed to Chrome.
                                  Sometimes Chrome need this flag to work together with Karma.
+ --user-data-dir=<...>         This flag will be passed to browsers to specify the user data directory.
  --chromium-flags=<...>        This flag will be passed to Chrome and Edge browsers. Can be used multiple times.
 
 Examples:
@@ -195,6 +196,7 @@ export interface TestRunnerCliArgs {
   webnnOptions?: InferenceSession.WebNNExecutionProviderOption;
   globalEnvFlags?: Test.Options['globalEnvFlags'];
   noSandbox?: boolean;
+  userDataDir?: string;
   chromiumFlags: string[];
 }
 
@@ -477,6 +479,9 @@ export function parseTestRunnerCliArgs(cmdlineArgs: string[]): TestRunnerCliArgs
   // Option: --no-sandbox
   const noSandbox = !!args['no-sandbox'];
 
+  // Option: --user-data-dir
+  const userDataDir = args['user-data-dir'];
+
   // parse chromium flags
   let chromiumFlags = args['chromium-flags'];
   if (!chromiumFlags) {
@@ -515,6 +520,7 @@ export function parseTestRunnerCliArgs(cmdlineArgs: string[]): TestRunnerCliArgs
     wasmOptions,
     globalEnvFlags,
     noSandbox,
+    userDataDir,
     chromiumFlags
   };
 }
diff --git a/js/web/script/test-runner-cli.ts b/js/web/script/test-runner-cli.ts
index ace64e9532b12..03d637b35bc7c 100644
--- a/js/web/script/test-runner-cli.ts
+++ b/js/web/script/test-runner-cli.ts
@@ -573,6 +573,9 @@ async function main() {
         karmaArgs.push('--log-level debug');
       }
       karmaArgs.push(`--bundle-mode=${args.bundleMode}`);
+      if (args.userDataDir) {
+        karmaArgs.push(`--user-data-dir="${args.userDataDir}"`);
+      }
       karmaArgs.push(...chromiumFlags.map(flag => `--chromium-flags=${flag}`));
       if (browser.startsWith('Edge')) {
         // There are currently 2 Edge browser launchers:
@@ -671,7 +674,7 @@ async function main() {
       case 'edge':
         return 'EdgeTest';
       case 'firefox':
-        return 'Firefox';
+        return 'FirefoxTest';
       case 'electron':
         return 'Electron';
       case 'safari':
diff --git a/tools/ci_build/github/azure-pipelines/templates/win-web-ci.yml b/tools/ci_build/github/azure-pipelines/templates/win-web-ci.yml
index 1eb2ee6f6409c..b7aee559cf73c 100644
--- a/tools/ci_build/github/azure-pipelines/templates/win-web-ci.yml
+++ b/tools/ci_build/github/azure-pipelines/templates/win-web-ci.yml
@@ -153,31 +153,61 @@ jobs:
       errorActionPreference: stop
     displayName: 'Pack NPM packages'
   - script: |
-     npm test -- -e=chrome -b=webgl,wasm --karma-debug
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+     mkdir $(Agent.TempDirectory)\web\test\01
+     npm test -- -e=chrome -b=webgl,wasm --user-data-dir=$(Agent.TempDirectory)\web\test\01
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests (wasm,webgl backend)'
-    condition: eq('${{ parameters.RunWebGpuTests }}', 'false')
+    condition: and(succeeded(), eq('${{ parameters.RunWebGpuTests }}', 'false'))
+  - script: |
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
   - script: |
-     npm test -- -e=chrome -b=webgl,wasm,webgpu --karma-debug $(webgpuCommandlineExtraFlags)
+     mkdir $(Agent.TempDirectory)\web\test\02
+     npm test -- -e=chrome -b=webgl,wasm,webgpu $(webgpuCommandlineExtraFlags) --user-data-dir=$(Agent.TempDirectory)\web\test\02
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests (ALL backends)'
-    condition: eq('${{ parameters.RunWebGpuTests }}', 'true')
+    condition: and(succeeded(), eq('${{ parameters.RunWebGpuTests }}', 'true'))
+  - script: |
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
   - script: |
-     npm test -- suite1 -e=chrome -b=webgpu --io-binding=gpu-tensor --karma-debug $(webgpuCommandlineExtraFlags)
+     mkdir $(Agent.TempDirectory)\web\test\03
+     npm test -- suite1 -e=chrome -b=webgpu --io-binding=gpu-tensor $(webgpuCommandlineExtraFlags) --user-data-dir=$(Agent.TempDirectory)\web\test\03
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests (Suite1, webgpu, IO-binding=gpu-tensor)'
-    condition: eq('${{ parameters.RunWebGpuTests }}', 'true')
+    condition: and(succeeded(), eq('${{ parameters.RunWebGpuTests }}', 'true'))
   - script: |
-     npm test -- suite1 -e=chrome -b=webgpu --io-binding=gpu-location --karma-debug $(webgpuCommandlineExtraFlags)
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+     mkdir $(Agent.TempDirectory)\web\test\04
+     npm test -- suite1 -e=chrome -b=webgpu --io-binding=gpu-location $(webgpuCommandlineExtraFlags) --user-data-dir=$(Agent.TempDirectory)\web\test\04
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests (Suite1, webgpu, IO-binding=gpu-location)'
-    condition: eq('${{ parameters.RunWebGpuTests }}', 'true')
+    condition: and(succeeded(), eq('${{ parameters.RunWebGpuTests }}', 'true'))
+  - script: |
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
   - script: |
-     npm test -- --webgl.pack -b=webgl -e=chrome --karma-debug
+     mkdir $(Agent.TempDirectory)\web\test\05
+     npm test -- --webgl.pack -b=webgl -e=chrome --user-data-dir=$(Agent.TempDirectory)\web\test\05
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests - WebGL: packed mode'
   - script: |
-     npm test -- --wasm.proxy -b=wasm -e=chrome --karma-debug
+     powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+     mkdir $(Agent.TempDirectory)\web\test\06
+     npm test -- --wasm.proxy -b=wasm -e=chrome --user-data-dir=$(Agent.TempDirectory)\web\test\06
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'Run ort-web tests - WebAssembly: proxy'
     condition: and(succeeded(), eq('${{ parameters.BuildConfig }}', 'Release'))
diff --git a/tools/ci_build/github/azure-pipelines/templates/win-web-multi-browsers.yml b/tools/ci_build/github/azure-pipelines/templates/win-web-multi-browsers.yml
index 79bf0b5e71363..46dad2c1847cb 100644
--- a/tools/ci_build/github/azure-pipelines/templates/win-web-multi-browsers.yml
+++ b/tools/ci_build/github/azure-pipelines/templates/win-web-multi-browsers.yml
@@ -68,15 +68,31 @@ jobs:
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'npm ci /js/web/'
   - script: |
-      npm test -- suite0 -b=wasm,webgl --wasm.initTimeout=30000 --file-cache
+      powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Chrome processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+      mkdir $(Agent.TempDirectory)\web\test_multi_browsers\01
+      npm test -- suite0 -e=chrome -b=wasm,webgl --wasm.initTimeout=30000 --file-cache --user-data-dir=$(Agent.TempDirectory)\web\test_multi_browsers\01
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'npm test (Suite0, Chrome)'
   - script: |
-      npm test -- suite0 -b=wasm,webgl -e=firefox --wasm.initTimeout=30000 --file-cache
+      powershell "Get-WmiObject Win32_Process -Filter \"name = 'firefox.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Firefox processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+      mkdir $(Agent.TempDirectory)\web\test_multi_browsers\02
+      powershell "Get-WmiObject Win32_Process -Filter \"name = 'chrome.exe'\" | Format-List CommandLine"
+      npm test -- suite0 -b=wasm,webgl -e=firefox --wasm.initTimeout=30000 --file-cache --user-data-dir=$(Agent.TempDirectory)\web\test_multi_browsers\02
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'npm test (Suite0, Firefox)'
   - script: |
-      npm test -- suite0 -b=wasm,webgl -e=edge --wasm.initTimeout=30000 --file-cache
+      powershell "Get-WmiObject Win32_Process -Filter \"name = 'msedge.exe'\" | Format-List CommandLine"
+    displayName: 'Check active Edge processes (before test)'
+    condition: and(succeeded(), eq('$(Agent.Diagnostic)', 'true'))
+  - script: |
+      mkdir $(Agent.TempDirectory)\web\test_multi_browsers\03
+      npm test -- suite0 -b=wasm,webgl -e=edge --wasm.initTimeout=30000 --file-cache --user-data-dir=$(Agent.TempDirectory)\web\test_multi_browsers\03
     workingDirectory: '$(Build.SourcesDirectory)\js\web'
     displayName: 'npm test (Suite0, Edge)'
   - task: mspremier.PostBuildCleanup.PostBuildCleanup-task.PostBuildCleanup@3