1. 8.4 Dynamic markup insertion
      1. 8.4.1 Opening the input stream
      2. 8.4.2 Closing the input stream
      3. 8.4.3 document.write()
      4. 8.4.4 document.writeln()

8.4 Dynamic markup insertion

APIs for dynamically inserting markup into the document interact with the parser, and thus their behavior varies depending on whether they are used with HTML documents (and the HTML parser) or XML documents (and the XML parser).

8.4.1 Opening the input stream

The open() method comes in several variants with different numbers of arguments.

document = document . open( [ type [, replace ] ] )

Causes the Document to be replaced in-place, as if it was a new Document object, but reusing the previous object, which is then returned.

If the type argument is omitted or has the value "text/html", then the resulting Document has an HTML parser associated with it, which can be given data to parse using document.write(). Otherwise, all content passed to document.write() will be parsed as plain text.

If the replace argument is present and has the value "replace", the existing entries in the session history for the Document object are removed.

The method has no effect if the Document is still being parsed.

Throws an "InvalidStateError" DOMException if the Document is an XML document.

Throws an "InvalidStateError" DOMException if the parser is currently executing a custom element constructor.

window = document . open( url, name, features )

Works like the window.open() method.

8.4.2 Closing the input stream

document . close()

Closes the input stream that was opened by the document.open() method.

Throws an "InvalidStateError" DOMException if the Document is an XML document.

Throws an "InvalidStateError" DOMException if the parser is currently executing a custom element constructor.

8.4.3 document.write()

document . write(text...)

In general, adds the given string(s) to the Document's input stream.

This method has very idiosyncratic behavior. In some cases, this method can affect the state of the HTML parser while the parser is running, resulting in a DOM that does not correspond to the source of the document (e.g. if the string written is the string "<plaintext>" or "<!--"). In other cases, the call can clear the current page first, as if document.open() had been called. In yet more cases, the method is simply ignored, or throws an exception. Users agents are explicitly allowed to avoid executing script elements inserted via this method. And to make matters even worse, the exact behavior of this method can in some cases be dependent on network latency, which can lead to failures that are very hard to debug. For all these reasons, use of this method is strongly discouraged.

Throws an "InvalidStateError" DOMException when invoked on XML documents.

Throws an "InvalidStateError" DOMException if the parser is currently executing a custom element constructor.

8.4.4 document.writeln()

document . writeln(text...)

Adds the given string(s) to the Document's input stream, followed by a newline character. If necessary, calls the open() method implicitly first.

Throws an "InvalidStateError" DOMException when invoked on XML documents.

Throws an "InvalidStateError" DOMException if the parser is currently executing a custom element constructor.