Develop Reference

Simple, standalone (i.e., no external files), offline, client-based solution for selecting file and displaying contents in HTML with Javascript

I'd sum this up as looking for an offline client solution that is 100% standalone and uses no external files/libraries or other machine resources to tabulate data from a user-chosen TSV file (the result is simply rendered in a plain HTML table - nothing fancy, just data).
I am not a web programmer, but have volunteered to do this project. I have been asked to code this as a browser-based solution because the party deems it the most user-friendly for their needs.
Again, this is not an html file that is served; it is emailed to a client that copies it into a folder of their choosing and run (by selecting a local file to render).
Every time I attempt some solution (e.g., FileReader, etc.), I can only get it to only work in a certain manner with specific browsers (including having to use it differently in the same code depending upon the browser - is this simply my lack of knowledge?).
My question is: Is there one single way to code this for most browsers (including older browsers like IE8)?
If not, I would most appreciate suggestions - both general and specific.
An example would be helpful if possible.
Thank you in advance.

If you're looking for client/browser specific, you won't have access to the file system. That's a security breach that isn't implemented into the browsers. You're going to need to implement some sort of server-side technology to take a crack at the file being handed over, or you will need to strictly specify which browsers are supported (things like FileReader are only IE10 or better).
I've never tried using the INPUT FILE to see if it will load a file before pushing it to the server (in say a FORM POST or a XHR/AJAX push)- but maybe look here:
https://developer.mozilla.org/en-US/docs/Using_files_from_web_applications
Let's see -- what else. If the file has a specific name, your HTML could reference it in an IFRAME and see if you can't communicate back and forth between the IFRAME and the parent window.
You're really limiting yourself without having a server being able to process it, and the browser range you need. Your best bet might be the File API and restrict the lower limit of browser compatibility?
http://www.html5rocks.com/en/tutorials/file/dndfiles/

AFAIK, there is no way to do this for all browsers. Especially for IE8. If you need a standalone application, the best way is to use C++/Java/C# or any language that allows to create desctop applications.

Parse markdown on the fly

I want to implement markdown to my forums.
I research many possible approaches how I would do that and this is what I thought:
A simple approach would involve pagedown on client side and php-markdown on the server.
My approach is to save pure markdown to database and when displaying convert to HTML (with pagedown). Since I already have security layer for my server side (HTML elements whitelist) and all the necessary staff I don't see anything to lose here.
What I win in this case? well I have to modify pagedown to use custom buttons and patterns. That would be hard for me to maintain both php and JavaScript.
My question is: is this good aproach?
To break this question:
Is there any serious overhead on client side loading about 30
posts and converting it to HTML (performance)
With the Idea that I check elements whitelist, is there any
security issue I need to know about? (Security)

I wouldn't use client side markdown engines. From a few quick googles its of the opinion it's very CPU intensive. Loading 30 posts would add quite a bit of overhead.
If you stored MD in the DB, rendered to HTML on the fly, then employed some caching (memcached or redis) that could work quite well.
In regards to security theres a good read here, it would require some extra sanitising removing scripts/links/redirects etc.
Further reading
http://functionn.in/resource/remarked-js
How to use Markdown & MySQL?

Converting markdown from client side is not recommended as #Lex has stated. Instead, you can use some online services to convert the markdown top html for you.
Have a look at http://daringfireball.net/projects/markdown/dingus. You can use curl or something to post markdown to the site and then scrap the website to take the html part.
You can also have a look at here http://parsedown.org/

You have two options to suggest:
Strapdown - allows to create markdown documents without server-side processing, as you can see on there page, even without code, just by using static files
markdown-js - allows to create markdown document with client-side processing (javascript)

Here is how I do it:
Save markdown code in db and at rendering I'm caching the result in a file (file, Memcached or any cache storage engine you want). This way I keep the original in database and I`m not wasting resources to compile markdown at each page visit, instead I serve the cache file until it has expired or deleted because of a change.

print html page to PDF on a schedule

I have a HTML page that uses javascript to generate dynamic images using a graph handler on a different server. The images will contain the same data for 1 week but will change when the 1 week window expires.
I am trying to come up with a way to automatically save the contents of the page to either a local file on the server or write to a PDF file.
I tried to use a 'web downloader' like HTTTrack, but it does not get the dynamic images...
I am running the html page off IIS.
I have no experience with IIS or ASP.
Thanks!

I'm not sure that I see any way to do this directly off the front end in an automatic manner. The challenge is that any "screen scraper" you have go out and grab the site with would need to be running javascript to get the tables, which isn't how I see many such systems operating. It's partially why you see strangeness on Archive.org when you have a site that's heavily augmented with javascript or flash.
An untested concept you might attempt was posted in this Stack Question
I could see some sort of a system that you rig together with another computer that schedules an browser load then prints to .pdf in some fashion. I've been unable to find any specific software that would automate that process, so you'd be left cobbling such a system together on your own.
Clearly you have the data available to make your dynamic images. The most feature-rich way I could think of would be to use a system like Jasper Reports or Crystal Reports, which you could feed your data, replicate the report, and easily output via pdf, a built-in export in both systems.
Perhaps its worth questioning your end purpose. To me, creating a "snapshot" of the relevant data in another table and using another system to render your graphs from that snapshot data seems far more valuable than just a print of the screen. You can then go back and adjust data as needed, or use it for other reporting purposes, exporting in any number of tools that are even as simple as Access. Heck, 10 years down the road you may want the data to look better than the graph system you're currently using, and you'd have the data to render it any way you want. When the VP of marketing comes looking for his numbers, a simple click would output those numbers that could be manipulated as needed from there.

I was able to accomplish what I wanted to do using wkhtmltopdf to convert my HTML page with Javascript to PDF. I ran the job via a task scheduler to supply my website url and output file name as parameters.
I then used a windows batch file to check if the file was created and then rename/email it to interested parties.
This of course requires that you have the ability to install wkhtmltopdf on your server.

Adding nodes to XML with a form

I've created a list using XML and have embedded an XSL stylesheet in it. Now I want to know, because this is a list of movies that constantly grows, is there a way to create a form that will add child and grandchild nodes to the list.
I'm thinking there might be some javascript involved, but I have no idea what I'm doing when it comes to scripting.

If the intension is to write new entries into this xml file you need to look at some form of serverside scripting. Javascript can not write to files.
PHP is probably the easiest to understand, start by buying a book that explains the basics with a few examples, it's not that hard to grasp, and a form and a simple function for writing to files shouldn't take you to long to figure out.
If you have no interest in that sort of thing, hire someone to do the job for you, it will probably only take a few hours for someone who knows what they are doing to get a complete system up and running for you, and unless you really would like to learn a serverside language that is probably the best option.

If you really want to do it all on the client side, you can try HTML5 client-side storage. This means the data will be persistent only for the user that enters the data (and only for the browser used to enter it, and only on the computer that was used).
If you want the movies to be accessible to multiple people, or from multiple computers, you need to use server-side storage.
FYI, HTML5 storage is not yet very well standardized across browsers.

Advice on starting JS or JQuery for file processing

My knowledge on web technologies (JS, JQ) are limited and I want to start learning them. As a starting point I want to do some file processing. Because it is something I have to do for my work and was planning to do it in Java. What I basically need to do is to go through a list of text files (assembly files) in a folder and search for routines and then list them. This is the first step and is a trivial task in Java.
But I wanted to take this a step further and do it in the browser, so that others in my team also can use it without installing anything (and also to impress them a little bit in the process. since I'm the new guy in the team :-)).
So when I input the folder, the script will go through the files and search and will display results in a web page. Basically first page will be a list of files in the folder, and clicking a file name will take me to another page which displays the routines in that file.
Sorry to bother you with details, but what I actually want to know are:
Is this possible with JS? (to
search for text patterns in a file)
Should I start with JS or JQ? (I
think many would recommend starting
with JS, but since this is a side
project and this is done purely in
my own time, would you suggest start
learning JQ because it's relatively
simpler to learn (from what I have
read) for a beginner?
Or should I just do the processing
in JAva and then interface the
results to a webpage
Any advice is appreciated.
Thank you very much.

Java and JavaScript have nothing to do with each other, jQuery is library written to simplify usage of JavaScript with some handy shortcuts.
I'm afraid JavaScript would not be able to parse text files as its main usage is manipulating content inside browser window and limited by different security policies.
To parse files you have to chose server side language.

maybe you can use java to deal with the file processing, and then send the result to js script , which will show these results to users.
js's ability is limited

For security reasons, JavaScript is sandboxed within the browser, and has basically no access to the local file system. From what you have described, it sounds like your best option is to use Java to process ...whatever...
This function has nothing to do with web browsing. Why is a browser the best tool for the job, anyway?