diff --git a/client/karma.js b/client/karma.js
index 97b3b62fe..c7f646963 100644
--- a/client/karma.js
+++ b/client/karma.js
@@ -62,12 +62,27 @@ function Karma (socket, iframe, opener, navigator, location) {
           childWindow.close()
         }
         childWindow = opener(url)
-      // run context on parent element and dynamically loading scripts
+      // run context on parent element (client_with_context)
+      // using window.__karma__.scriptUrls to get the html element strings and load them dynamically
       } else if (url !== 'about:blank') {
         var loadScript = function (idx) {
           if (idx < window.__karma__.scriptUrls.length) {
-            var ele = document.createElement('script')
-            ele.src = window.__karma__.scriptUrls[idx]
+            var parser = new DOMParser()
+            // Revert escaped characters with special roles in HTML before parsing
+            var string = window.__karma__.scriptUrls[idx]
+              .replace(/\\x3C/g, '<')
+              .replace(/\\x3E/g, '>')
+            var doc = parser.parseFromString(string, 'text/html')
+            var ele = doc.head.firstChild || doc.body.firstChild
+            // script elements created by DomParser are marked as unexecutable,
+            // create a new script element manually and copy necessary properties
+            // so it is executable
+            if (ele.tagName && ele.tagName.toLowerCase() === 'script') {
+              var tmp = ele
+              ele = document.createElement('script')
+              ele.src = tmp.src
+              ele.crossOrigin = tmp.crossOrigin
+            }
             ele.onload = function () {
               loadScript(idx + 1)
             }
diff --git a/lib/middleware/karma.js b/lib/middleware/karma.js
index c51c34491..cf7a93ec6 100644
--- a/lib/middleware/karma.js
+++ b/lib/middleware/karma.js
@@ -175,7 +175,6 @@ function createKarmaMiddleware (
           common.setNoCacheHeaders(response)
 
           const scriptTags = []
-          const scriptUrls = []
           for (const file of files.included) {
             let filePath = file.path
             const fileType = file.type || path.extname(filePath).substring(1)
@@ -192,8 +191,6 @@ function createKarmaMiddleware (
               }
             }
 
-            scriptUrls.push(filePath)
-
             if (fileType === 'css') {
               scriptTags.push(`<link type="text/css" href="${filePath}" rel="stylesheet">`)
             } else if (fileType === 'dom') {
@@ -207,6 +204,20 @@ function createKarmaMiddleware (
             }
           }
 
+          const scriptUrls = []
+          // For client_with_context, html elements are not added directly through an iframe.
+          // Instead, scriptTags is stored to window.__karma__.scriptUrls first. Later, the
+          // client will read window.__karma__.scriptUrls and dynamically add them to the DOM
+          // using DOMParser.
+          if (requestUrl === '/client_with_context.html') {
+            for (const script of scriptTags) {
+              scriptUrls.push(
+                // Escape characters with special roles (tags) in HTML. Open angle brackets are parsed as tags
+                // immediately, even if it is within double quotations in browsers
+                script.replace(/</g, '\\x3C').replace(/>/g, '\\x3E'))
+            }
+          }
+
           const mappings = data.includes('%MAPPINGS%') ? files.served.map((file) => {
             const filePath = filePathToUrlPath(file.path, basePath, urlRoot, proxyPath)
               .replace(/\\/g, '\\\\') // Windows paths contain backslashes and generate bad IDs if not escaped