From http://www.w3schools.com (Copyright Refsnes Data)
To help you validate your wml, we have used The Microsoft's XML parser to create a wml validator. Paste your wml in the text area, and validate it by pressing the validate button.
You can also validate your wml files, simply by typing the url of your wml file and press the submit button
If you want to validate an error free WML file you can paste this address into the name field: http://www.w3schools.com/wap/demo_helloworld.wml
NOTE: This example validates the wml file according to its DTD, this validation is only supported by Internet Explorer.
NOTE: If you get an error message saying "Access denied" when accessing this file, it is because your Internet Explorer security setting do not allow access across domains.
From http://www.w3schools.com (Copyright Refsnes Data)