This is an error when the attribute name is wrong, or the attribute value is wrong. For example:

1. When MSV sees an unexpected attribute name:

   <img hreeef="logo.gif"/>
   
   
   When an attribute value does not match the specified datatype.
   For example, the following document causes this error if the "width"
   attribute is specified as the int type.
   
   <img href="logo.gif" width="twenty four pixels" />
   
   
   

This error is reported in the startElement callback.

Currently, the application cannot easily distinguish whether this error is caused by an invalid attribute value, or invalid attribute name. It is also non-trivial for MSV to detect this difference correctly. But there maybe applications to which this difference is important. I welcome any comments on this issue.

This type of error occurs when MSV finds an unexpected tag name. For example:

1. When a tag name appears where it is not valid to appear.

   <html>
     <head> ... </head>
     <head> ... </head> <!-- head cannot appear here -->
     <body> ... </body>
   </html>
   </pre>
   
   
   When there is a typo in the tag name.
   <html>
     <heed> ... </heed> <!-- typo -->
     <body> ... </body>
   </pre>
   
   
   When an element appears where no element is allowed at all.
   <html>
     <head>
       <meta ...>
         <junk/>   <!-- meta cannot have any children -->
   
   
   

This error is reported when the startElement callback is called.

This type of errors indicate that the document contains PCDATA but it is not good. Here are typical examples of this error.

1. PCDATA appears where no text is allowed at all. For example:

   <html>
     <head> ... </head>
     ** invalid text **
     <body> ... </body>
   </html>
   

2. text was not a correct value for the given datatype. For example,

   <!-- when "integer" is expected -->
   <length> five </length>
   

Usually, the user can fix this error by removing or chaning the text.

MSV validates text after it collects the whole string. That means MSV does not validate text in the SAX's characters callback. As a result, this error is reported after the next start tag or end tag is found.

For example, in the above example, the error is reported when MSV reads <body>(start tag) and </length> (end tag) respectively.

<html>
  <head> ... </head>
</html>  <!-- where is the body element? -->

Usually, this means that additional elements and/or PCDATA are necessary to make the document valid.

Fields of the class provide information about enclosing tag. (In case of the above example, it is html.)

This type of error occurs only when required attributes are missing. Note that the fields of this class provide information about the element, not the attribute which is missing.

<img/>  <!-- where is the href attribute? -->