avoid setting innerHTML value

Former-commit-id: b52f98e6a701092a633da1068c769c6a5cf1f755

lib/single-file/modules/html-serializer.js

@@ -117,7 +117,7 @@ this.singlefile.lib.modules.serializer = this.singlefile.lib.modules.serializer
 			content += ">";
 		}
 		if (element.tagName == "TEMPLATE") {
-			content += element.innerHTML;
+			content += element.innerHTML || element.textContent;
 		} else {
 			Array.from(element.childNodes).forEach(childNode => content += serialize(childNode, compressHTML));
 		}

lib/single-file/single-file-helper.js

@@ -94,7 +94,7 @@ this.singlefile.lib.helper = this.singlefile.lib.helper || (() => {
 		doc.querySelectorAll("noscript").forEach(element => {
 			const disabledNoscriptElement = doc.createElement("template");
 			disabledNoscriptElement.setAttribute(DISABLED_NOSCRIPT_ATTRIBUTE_NAME, "");
-			disabledNoscriptElement.innerHTML = element.textContent;
+			disabledNoscriptElement.textContent = element.textContent;
 			element.parentElement.replaceChild(disabledNoscriptElement, element);
 		});
 		initDoc(doc);
@@ -312,7 +312,7 @@ this.singlefile.lib.helper = this.singlefile.lib.helper || (() => {
 	function postProcessDoc(doc, markedElements) {
 		doc.querySelectorAll("[" + DISABLED_NOSCRIPT_ATTRIBUTE_NAME + "]").forEach(element => {
 			const noscriptElement = doc.createElement("noscript");
-			noscriptElement.textContent = element.innerHTML;
+			noscriptElement.textContent = element.innerHTML || element.textContent;
 			element.parentElement.replaceChild(noscriptElement, element);
 		});
 		doc.querySelectorAll("meta[disabled-http-equiv]").forEach(element => {