diff --git a/Sources/BrowserServicesKit/ContentBlocking/UserScripts/surrogates.js b/Sources/BrowserServicesKit/ContentBlocking/UserScripts/surrogates.js
index c76d0ff71..b15153721 100644
--- a/Sources/BrowserServicesKit/ContentBlocking/UserScripts/surrogates.js
+++ b/Sources/BrowserServicesKit/ContentBlocking/UserScripts/surrogates.js
@@ -1,5 +1,5 @@
 //
-//  contentblocker.js
+//  surrogates.js
 //  DuckDuckGo
 //
 //  Copyright © 2017 DuckDuckGo. All rights reserved.
@@ -466,8 +466,6 @@
         }
     }
 
-    const loadedSurrogates = {}
-
     // private
     function loadSurrogate (surrogatePattern) {
         trackers.surrogateList[surrogatePattern]()
@@ -475,7 +473,6 @@
 
     // public
     function shouldBlock (trackerUrl, type, element) {
-        seenUrls.add(trackerUrl)
         const startTime = performance.now()
 
         if (!blockingEnabled) {
@@ -508,15 +505,15 @@
             if (element && element.onerror) {
                 element.onerror = () => {}
             }
-            if (!loadedSurrogates[result.matchedRule.surrogate]) {
+            try {
                 loadSurrogate(result.matchedRule.surrogate)
-                loadedSurrogates[result.matchedRule.surrogate] = true
                 // Trigger a load event on the original element
                 if (element && element.onload) {
                     element.onload(new Event('load'))
                 }
+            } catch (e) {
+                duckduckgoDebugMessaging.log(`error loading surrogate: ${e.toString()}`)
             }
-
             const pageUrl = window.location.href
             surrogateInjected({
                 url: trackerUrl,
@@ -538,108 +535,28 @@
         return false
     }
 
-    const seenUrls = new Set()
-    function hasNotSeen (url) {
-        // Ignore elements with no url
-        if (!url) {
-            return false
-        }
-        return !seenUrls.has(url)
-    }
-
-    function processPage () {
-        [...document.scripts].filter((el) => hasNotSeen(el.src)).forEach((el) => {
-            if (shouldBlock(el.src, 'script', el)) {
-                duckduckgoDebugMessaging.log('blocking load')
-            }
-        });
-        [...document.images].filter((el) => hasNotSeen(el.src)).forEach((el) => {
-            // If the image's natural width is zero, then it has not loaded so we
-            // can assume that it may have been blocked.
-            if (el.naturalWidth === 0) {
-                if (shouldBlock(el.src, 'image', el)) {
-                    duckduckgoDebugMessaging.log('blocking load')
-                }
-            }
-        });
-        [...document.querySelectorAll('link')].filter((el) => hasNotSeen(el.href)).forEach((el) => {
-            if (shouldBlock(el.href, el.rel, el)) {
-                duckduckgoDebugMessaging.log('blocking load')
-            }
-        });
-        [...document.querySelectorAll('iframe')].filter((el) => hasNotSeen(el.src)).forEach((el) => {
-            if (shouldBlock(el.src, 'subdocument', el)) {
-                duckduckgoDebugMessaging.log('blocking load')
-            }
-        })
-    }
-
-    function debounce (func, wait) {
-        let timeout
-        return function () {
-            clearTimeout(timeout)
-            timeout = setTimeout(() => {
-                func.apply(this, arguments)
-            }, wait)
-        }
-    }
-
-    const observer = new MutationObserver(debounce((mutations, o) => {
-        processPage()
-    }, 100))
-    const rootElement = document.body || document.documentElement
-    observer.observe(rootElement, { childList: true, subtree: true });
-
-    // Init
-    (function () {
-        duckduckgoDebugMessaging.log('installing load detection')
-        window.addEventListener('load', function (event) {
-            processPage()
-        }, false)
-
-        try {
-            duckduckgoDebugMessaging.log('installing image src detection')
-
-            const originalImageSrc = Object.getOwnPropertyDescriptor(Image.prototype, 'src')
-            Object.defineProperty(Image.prototype, 'src', {
-                writable: true, // Needs to be writable for the content blocking rules script. Will be locked down in that script
-                get: function () {
-                    return originalImageSrc.get.call(this)
-                },
-                set: function (value) {
-                    const instance = this
-                    if (shouldBlock(value, 'image')) {
-                        duckduckgoDebugMessaging.log('blocking image src: ' + value)
-                    } else {
-                        originalImageSrc.set.call(instance, value)
+    const observer = new MutationObserver((records) => {
+        for (const record of records) {
+            record.addedNodes.forEach((node) => {
+                if (node instanceof HTMLScriptElement) {
+                    if (shouldBlock(node.src, 'script', node)) {
+                        duckduckgoDebugMessaging.log('blocking load')
                     }
                 }
             })
-        } catch (error) {
-            duckduckgoDebugMessaging.log('failed to install image src detection')
-        }
-
-        try {
-            duckduckgoDebugMessaging.log('installing xhr detection')
-
-            const xhr = XMLHttpRequest.prototype
-            const originalOpen = xhr.open
-
-            xhr.open = function () {
-                const args = arguments
-                const url = arguments[1]
-                if (shouldBlock(url, 'xmlhttprequest')) {
-                    args[1] = 'about:blank'
+            if (record.target instanceof HTMLScriptElement) {
+                if (shouldBlock(record.target.src, 'script', record.target)) {
+                    duckduckgoDebugMessaging.log('blocking load')
                 }
-                duckduckgoDebugMessaging.log('sending xhr ' + url + ' to ' + args[1])
-                return originalOpen.apply(this, args)
             }
-        } catch (error) {
-            duckduckgoDebugMessaging.log('failed to install xhr detection')
         }
-
-        duckduckgoDebugMessaging.log('content blocking initialised')
-    })()
+    })
+    const rootElement = document.body || document.documentElement
+    observer.observe(rootElement, {
+        childList: true, 
+        subtree: true, 
+        attributeFilter: ['src']
+    });
 
     return {
         shouldBlock: shouldBlock