I found that at lines 72 and 80 the Response.Write statements contain an error where the "alt" HTML attribute is specified.

 

At both lines you can read something like:

 

.....alt=" & strTxtReadMessage & " border=.....

 

This doesn't raise an error, but in the case variable contains spaces (e.g.: "This is my alternative text"), the rendered HTML is incorrect, like

 

.....alt=This is my alternative text border=.....

 

and the relative tooltip shown by the browser, obviously, is This

 

The problem is the missing couple of double quotes.

 

The code should be similar to:

 

.....alt=""" & strTxtReadMessage & """ border=.....

 

which would be rendered in HTML as

 

.....alt="This is my alternative text" border=.....

 

and the relative tooltip shown by the browser, obviously, would be This is my alternative text