How to replace Node innerHTML and save it to new string?

Is it able to replace node innerHTML, like this:

```
for node in process(everydayHtmlString, '//table[@id="zhuye" or @id="fuye"]') do
begin
if node.toNode.getAttribute('id') = 'zhuye' then
begin
node.toNode.innerHTML := aStringContainHTML;
end;
end;
```

and what is the proper way to update `everydayHtmlString` variable to the latest？

The issue names process(...), the XPath selection, node.toNode, and everydayHtmlString; start by tracing how parsed HTML nodes are represented and how the source string is produced. Confirm the supported way to replace innerHTML and serialize the updated tree back into everydayHtmlString, using the zhuye node as the minimal example.

Written by the indexing model from the issue text.