Method add

src/main/java/org/htmlunit/html/DoTypeProcessor.java:140–148

(final StringBuilder newValue, final char c, final int selectionStart,
            final int selectionEnd)

    }

    private static void add(final StringBuilder newValue, final char c, final int selectionStart,
            final int selectionEnd) {
        if (selectionStart == newValue.length()) {
            newValue.append(c);
        }
        else {
            newValue.replace(selectionStart, selectionEnd, Character.toString(c));
        }
    }

    private static void add(final StringBuilder newValue, final String string, final int selectionStart,
            final int selectionEnd) {