This attribute returns the text content of this node and its descendants. When it is defined to be null, setting it has no effect. On setting, any possible children this node may have are removed and, if it the new string is not empty or null, replaced by a single Text node containing the string this attribute is set to.
On getting, no serialization is performed, the returned string does not contain any markup. No whitespace normalization is performed and the returned string does not contain the white spaces in element content (see the attribute Text.isElementContentWhitespace). Similarly, on setting, no parsing is performed either, the input string is taken as pure textual content.
The string returned is made of the text content of this node depending on its type, as defined below:

Node/Content table

Node type	Content
ELEMENT_NODE, ATTRIBUTE_NODE, ENTITY_NODE, ENTITY_REFERENCE_NODE, DOCUMENT_FRAGMENT_NODE	concatenation of the textContent attribute value of every child node, excluding COMMENT_NODE and PROCESSING_INSTRUCTION_NODE nodes. This is the empty string if the node has no children.
TEXT_NODE, CDATA_SECTION_NODE, COMMENT_NODE, PROCESSING_INSTRUCTION_NODE	nodeValue
DOCUMENT_NODE, DOCUMENT_TYPE_NODE, NOTATION_NODE	null

Exceptions:

DOMException

DOMSTRING_SIZE_ERR: Raised when it would return more characters than fit in a DOMString variable on the implementation platform.

Since:  1.5, DOM Level 3