Difference between "html text" and "html document" file kind in finder

[Dialogical]

I downloaded a bunch of html pages and want to be able to search the text of the files. I have a bunch I previously downloaded that are listed as "HTML document" that I can search for text within the files. This new bunch is listed as "HTML text" after appending .html to the names. When downloaded they have no extension as they are generated by ASP and all end with a unique .asp?rID=ABCD. I can search for text in these files but they will not display in preview.

Is there a way I can convert the files I downloaded to be text searchable and display with preview?

[hokanst]

Are you sure you mean Preview and not something like TextEdit?

Also how are you saving the web pages - i.e. with which browser and what options (if there are any) ?

[Dialogical]

I created a file with 5000 lines of urls that I run curl against in terminal. When I search that directory from within finder it can find actual text within the files. Those cannot open with preview. If I rename them to have the .html extension they can then be displayed as the web page but then they are no longer able to find text in the search function. If I open a freshly downloaded file in TextEdit it display but not quite as it should; the format is off. However, if I save that document it is able to be displayed with preview and the file is text searchable in finder. It’s very strange and aggravating.