Writing Data from the HTML controls to Text File.

I want to write the data entered in the HTML controls such as "Textbox", "Combobox" to a Text file using HTML or Javascript.

If you are talking about writing the data to the Client computer then that is currently not an officially supported JavaScript ability. Officially, JavaScript is a 'sandbox' and you can not read/write to the host computer. With that said, M$ has added an ActiveX to IE that will allow you to read/write to the host computer IF ActiveX is turned on and you are using a newer version of IE. Alex posted a code sample elsewhere showing how he builds the redistributable version of the JS file and in that example he uses this IE object. Do a search of the forum, you should be able to find it.

Is that mean read/write to host computer can work , but read/write to client computer is still cannot work (using javascript or activeX or else)?

If you want to write the data on the Server, you would need a script that does that for you (PHP, ASP, JSP,...), you can not do this with pure HTML/Javascript.

If you want to write the data to the Client you could use cookies.

well you can write in the client if and only if he is using mozilla and enable remote permitions