diff --git a/xml/xml-psi-impl/src/com/intellij/lexer/BaseHtmlLexer.java b/xml/xml-psi-impl/src/com/intellij/lexer/BaseHtmlLexer.java
index c0030d89ff57..23d755a2c250 100644
--- a/xml/xml-psi-impl/src/com/intellij/lexer/BaseHtmlLexer.java
+++ b/xml/xml-psi-impl/src/com/intellij/lexer/BaseHtmlLexer.java
@@ -25,6 +25,7 @@ import com.intellij.psi.tree.IElementType;
 import com.intellij.psi.tree.TokenSet;
 import com.intellij.psi.xml.XmlTokenType;
 import com.intellij.util.text.CharArrayUtil;
+import com.intellij.xml.util.documentation.HtmlDescriptorsTable;
 import org.jetbrains.annotations.NonNls;
 import org.jetbrains.annotations.NotNull;
 import org.jetbrains.annotations.Nullable;
@@ -111,7 +112,8 @@ abstract class BaseHtmlLexer extends DelegateLexer {
       final boolean style = name.equals(TOKEN_STYLE);
       final int state = getState() & BASE_STATE_MASK;
       final boolean script = name.equals(TOKEN_SCRIPT) ||
-                       ((name.startsWith(TOKEN_ON) && name.indexOf(':') == -1 && !isHtmlTagState(state)));
+                       ((name.startsWith(TOKEN_ON) && name.indexOf(':') == -1 && !isHtmlTagState(state) &&
+                         HtmlDescriptorsTable.getAttributeDescriptor(name) != null));
 
       if (style || script) {
         // encountered tag name in end of tag
diff --git a/xml/xml-psi-impl/src/com/intellij/xml/util/documentation/HtmlDescriptorsTable.java b/xml/xml-psi-impl/src/com/intellij/xml/util/documentation/HtmlDescriptorsTable.java
index ed02f3af1c14..c19805412628 100644
--- a/xml/xml-psi-impl/src/com/intellij/xml/util/documentation/HtmlDescriptorsTable.java
+++ b/xml/xml-psi-impl/src/com/intellij/xml/util/documentation/HtmlDescriptorsTable.java
@@ -192,7 +192,7 @@ public class HtmlDescriptorsTable {
     return ourTagTable.get(tagName);
   }
 
-  static HtmlAttributeDescriptor getAttributeDescriptor(String attributeName) {
+  public static HtmlAttributeDescriptor getAttributeDescriptor(String attributeName) {
     return ourAttributeTable.get(attributeName);
   }