Constraints:
'<' (less-than) must be escaped as < otherwise the parse will assume you've started a tag.
'&' (ampersand) must be escaped as & otherwise it parse will assume you've started a entity reference.
Text is allowed within an element, comment, or processing instruction.
Text inside comments and processing instructions need not be escaped.
An entity reference allows you to escape characters.
These are pre-defined:
| Character | Entity Reference |
|---|---|
| & | & |
| < | < |
| > | > |
| ' | ' |
| " | " |