diff --git a/Build/Sources/TypeScript/backend/utility.ts b/Build/Sources/TypeScript/backend/utility.ts
index c4dfd2ada2a1a922380d1b4a69da52078c6c9212..e99b3d3cdcd8f8f977c1f091256e4a6af0c098bc 100644
--- a/Build/Sources/TypeScript/backend/utility.ts
+++ b/Build/Sources/TypeScript/backend/utility.ts
@@ -129,11 +129,12 @@ class Utility {
       const value = element.value;
 
       if (name) {
-        if (element instanceof HTMLInputElement && element.type == 'checkbox') {
+        if (element.tagName.toLowerCase() === 'input' && element.type == 'checkbox') {
+          const checkbox = element as HTMLInputElement;
           if (obj[name] === undefined) {
             obj[name] = [];
           }
-          if (element.checked){
+          if (checkbox.checked){
             obj[name].push(value);
           }
 
diff --git a/typo3/sysext/backend/Resources/Public/JavaScript/utility.js b/typo3/sysext/backend/Resources/Public/JavaScript/utility.js
index 3e4827278535f655faed4b39b8da5860e279b93d..a6c1688d14e4efb8339d755644db4e4e46064d10 100644
--- a/typo3/sysext/backend/Resources/Public/JavaScript/utility.js
+++ b/typo3/sysext/backend/Resources/Public/JavaScript/utility.js
@@ -10,4 +10,4 @@
  *
  * The TYPO3 project - inspiring people to share!
  */
-class Utility{static trimExplode(t,e){return e.split(t).map((t=>t.trim())).filter((t=>""!==t))}static trimItems(t){return t.map((t=>t instanceof String?t.trim():t))}static intExplode(t,e,r=!1){return e.split(t).map((t=>parseInt(t,10))).filter((t=>!isNaN(t)||r&&0===t))}static isNumber(t){return!isNaN(parseFloat(t.toString()))&&isFinite(t)}static getParameterFromUrl(t,e){if(console.warn("The function `getParameterFromUrl()` of `@typo3/backend/utility` has been marked as deprecated and will be removed in TYPO3 v13. Use `new URL(url, window.location.origin).searchParams.get(parameter)` instead."),"function"!=typeof t.split)return"";const r=t.split("?");let i="";if(r.length>=2){const t=r.join("?"),n=encodeURIComponent(e)+"=",a=t.split(/[&;]/g);for(let t=a.length;t-- >0;)if(-1!==a[t].lastIndexOf(n,0)){i=a[t].split("=")[1];break}}return i}static updateQueryStringParameter(t,e,r){const i=new RegExp("([?&])"+e+"=.*?(&|$)","i"),n=t.includes("?")?"&":"?";return t.match(i)?t.replace(i,"$1"+e+"="+r+"$2"):t+n+e+"="+r}static convertFormToObject(t){const e={};return t.querySelectorAll("input, select, textarea").forEach((t=>{const r=t.name,i=t.value;r&&(t instanceof HTMLInputElement&&"checkbox"==t.type?(void 0===e[r]&&(e[r]=[]),t.checked&&e[r].push(i)):e[r]=i)})),e}static mergeDeep(...t){const e=t=>t&&"object"==typeof t;return t.reduce(((t,r)=>(Object.keys(r).forEach((i=>{const n=t[i],a=r[i];Array.isArray(n)&&Array.isArray(a)?t[i]=n.concat(...a):e(n)&&e(a)?t[i]=Utility.mergeDeep(n,a):t[i]=a})),t)),{})}static urlsPointToSameServerSideResource(t,e){if(!t||!e)return!1;const r=window.location.origin;try{const i=new URL(t,Utility.isValidUrl(t)?void 0:r),n=new URL(e,Utility.isValidUrl(e)?void 0:r),a=i.origin+i.pathname+i.search;return a===n.origin+n.pathname+n.search}catch(t){return!1}}static isValidUrl(t){try{return new URL(t),!0}catch(t){return!1}}}export default Utility;
\ No newline at end of file
+class Utility{static trimExplode(t,e){return e.split(t).map((t=>t.trim())).filter((t=>""!==t))}static trimItems(t){return t.map((t=>t instanceof String?t.trim():t))}static intExplode(t,e,r=!1){return e.split(t).map((t=>parseInt(t,10))).filter((t=>!isNaN(t)||r&&0===t))}static isNumber(t){return!isNaN(parseFloat(t.toString()))&&isFinite(t)}static getParameterFromUrl(t,e){if(console.warn("The function `getParameterFromUrl()` of `@typo3/backend/utility` has been marked as deprecated and will be removed in TYPO3 v13. Use `new URL(url, window.location.origin).searchParams.get(parameter)` instead."),"function"!=typeof t.split)return"";const r=t.split("?");let i="";if(r.length>=2){const t=r.join("?"),a=encodeURIComponent(e)+"=",n=t.split(/[&;]/g);for(let t=n.length;t-- >0;)if(-1!==n[t].lastIndexOf(a,0)){i=n[t].split("=")[1];break}}return i}static updateQueryStringParameter(t,e,r){const i=new RegExp("([?&])"+e+"=.*?(&|$)","i"),a=t.includes("?")?"&":"?";return t.match(i)?t.replace(i,"$1"+e+"="+r+"$2"):t+a+e+"="+r}static convertFormToObject(t){const e={};return t.querySelectorAll("input, select, textarea").forEach((t=>{const r=t.name,i=t.value;if(r)if("input"===t.tagName.toLowerCase()&&"checkbox"==t.type){const a=t;void 0===e[r]&&(e[r]=[]),a.checked&&e[r].push(i)}else e[r]=i})),e}static mergeDeep(...t){const e=t=>t&&"object"==typeof t;return t.reduce(((t,r)=>(Object.keys(r).forEach((i=>{const a=t[i],n=r[i];Array.isArray(a)&&Array.isArray(n)?t[i]=a.concat(...n):e(a)&&e(n)?t[i]=Utility.mergeDeep(a,n):t[i]=n})),t)),{})}static urlsPointToSameServerSideResource(t,e){if(!t||!e)return!1;const r=window.location.origin;try{const i=new URL(t,Utility.isValidUrl(t)?void 0:r),a=new URL(e,Utility.isValidUrl(e)?void 0:r),n=i.origin+i.pathname+i.search;return n===a.origin+a.pathname+a.search}catch(t){return!1}}static isValidUrl(t){try{return new URL(t),!0}catch(t){return!1}}}export default Utility;
\ No newline at end of file