The reference to entity “w” must end with the ';' delimiter exception

The reference to entity “w” must end with the ';' delimiter exception

This is just a small tip. I get this error when adding a blog directory button image. I just figure this out and i think it will be helpful to anyone who experience this kind of error. 

So this is the code with error given by blog directory.

<a href='http://www.blogkeen.com/visit_blog.aspx?id=516512&mid=114464&f=true' target='_blank'

and here's the working code

<a href='http://www.blogkeen.com/visit_blog.aspx?id=516512&amp;mid=114464&amp;f=true' target='_blank'

Don't get it?

& is a special/functional char in HTML/XML but you want to use it as a normal char. So you have to encode it correctly: Write &amp; instead of &:

Hope this small tip helps =)