StartTag: invalid element name
A < that does not start a valid element name.
The message, as the validator reports it
StartTag: invalid element name
Why it happens
- A bare
<in text:a < b. In XML text it must be escaped. - An element name that starts with a digit, a hyphen or a period:
<1item>. - Characters not allowed in names, or a space right after
<.
How to fix it
Escape a literal < in text as < (or put the text in CDATA). Element names must start with a letter or _.
Example
Reports the error
<expr>a < b</expr>
Fixed
<expr>a < b</expr>