diff --git a/modules/editor/skins/simpleeditor/js/simpleeditor.js b/modules/editor/skins/simpleeditor/js/simpleeditor.js
index a8181b04e..2cfda25b5 100644
--- a/modules/editor/skins/simpleeditor/js/simpleeditor.js
+++ b/modules/editor/skins/simpleeditor/js/simpleeditor.js
@@ -42,8 +42,9 @@
 	// Simplify HTML content by removing unnecessary tags.
 	var simplifyContent = function(str) {
 		str = String(str);
-		str = str.replace(/<!--(.*?)-->/g, '');
-		str = str.replace(/<\/?(\?xml|meta|link|font|style|script|noscript|frame|noframes)\b[^>]*?>/ig, '');
+		str = str.replace(/<!--(.*?)-->/gs, '');
+		str = str.replace(/<\/?(\?xml|meta|link|font|span|style|script|noscript|frame|noframes|(?:st1|o):[a-z0-9]+)\b[^>]*?>/ig, '');
+		str = str.replace(/(id|class|style|on(?:[a-z0-9]+)|Mso(?:[a-z0-9]+))="[^"]*"/ig, '');
 		str = str.replace(/(<\/?)div(\W)/g, '$1p$2');
 		return str;
 	};