Develop Reference

Atom: Where is the list with all the default snippets?

Or do I just have to manually type in each letter to see what it could be tabbed into? And change the file extension to see the language-specific snippets?

I don't know about all of the snippets but for single languages, at a time you can go into Settings \ Packages and search for the language that you want. Then once you have found it scroll down until you find the snippets section and voilà, there are your snippets.
I know this is 7 months too late, but I just thought I would answer in case anyone else came looking for an answer like I did. :D
Edit: Just remembered something else, you can type snippets available in the command palette and see all the snippets for the file type you are focused on.

Extract document extensions from clicks

I'm using this technique to extract the click events in my SharePoint site. It uses jquery and a regular expression to capture clicks and report them as events to google analytics.
I'm also just past total newbie with regex -- It is starting to make some sense to me, but I have a lot to learn still. So here goes.
I have a preapproved list of filetypes that I am interested in based on the site listed above.
var filetypes = /\.(zip|pdf|doc.*|xls.*|ppt.*|mp3|txt|wma|mov|avi|wmv|flv|wav|jpg)$/i;
But it isn't quite working like I need. With the $ I assume it is trying to match to the end of the line. But often in SharePoint we get links like this:
example.org/sharepoint/_layouts/15/wopiframe.aspx?sourcedoc=/sharepointlibrary/the%20document%20name.docx&action=default&defaultitemopen=1
The two problems I have are, I can't count on the file name being before the query or hash and I can't count on it being at the end. And all the different Microsoft Office extensions.
I found this thread on extracting extensions, but it doesn't seem to work correctly.
I've put together this version
var filetypes = \.(zip|pdf|doc|xls|ppt|mp3|txt|wma|mov|avi|wmv|flv|wav|jpg)[A-Za-z]*
I changed the office bits from doc.* to just plain doc and added the optional alpha character afterwards. And removed the $ end anchor. It seems to be working with my test sample, but I don't know if there are gotchas that I don't understand.
Does this seem like a good solution or is there a better way to get a predetermined list of extensions (including for example the Office varions like doc, docx, docm) that is either before the query string or might be one parameter in the query string?

I would go with the following which matches file name and extension:
/[^/]+\.(zip|pdf|doc[xm]?|xlsx?|ppt|mp3|txt|wma|mov|avi|wmv|flv|wav|jpg)/i
Outputs the%20document%20name.docx from you example.
There may be other formats that it might not work on but should get you what you want.

HTML textarea spellcheck: How to tell if user makes spelling errors

I have a textarea that is defined thus:
<textarea spellcheck="true"></textarea>
When users type, spelling mistakes are highlighted to them (using a red underline, for my browser). Is there any way (using jQuery) to check whether there are spelling mistakes before a user submits the form?
This is what I want to achieve:
Form input textarea: [Typing some text in thsi box] [submit]
Before the user clicks submit, I would like a listener to "catch" the fact that "thsi" was spelled incorrectly and prompt the user. Is there any way to do this via the html5 spellcheck method, or do I have to use a custom javascript function for the spellchecking and listening?

A quick search brought up this jQuery plug-in that seems to do exactly what you want and it uses the Google spell-checking API https://code.google.com/p/jquery-spellchecker/wiki/Documentation
There is also Typo.js https://github.com/cfinke/Typo.js, which is a client-side based library. It does not use any API, instead it uses Hunspell-style dictionaries and it is only available for American English "EN_US".
If you don't want to use a plug-in or an existing code snippet, you can build your own by sending an ajax request to check the typed text against a service provider (Google in this case).

you can use jquery plugin for checking spelling.
i hope it helps you, thanks.
JavaScript SpellCheck
http://www.javascriptspellcheck.com/

If you have to build it natively you might consider building a Trie datastructure for this
check this Trie reference 1
Trie reference 2
Hope this helps

You have different ways to achieve it, it depends if your spelling has to be focused on a subject (like medical word spelling) or is it general.
Create yourself a dictionary (not the best choice and too long to make)
make a query to online dictionaries like google
try Jspell Evolution (the installation is a little annoying but once done it works very well Jspell Evolution website
you can look at typo.js typo.js article
Yesterday I found this article that is 10 times better than the others :
Article for javascript spell check locales where you can also have spelling for other languages/locales and not only english locale.

Fulltext search ignoring comments

I want fulltext search for my JavaScript code, but I'm usually not interested in matches from the comments.
How can I have fulltext search ignoring any commented match? Such a feature would increase my productivity as a programmer.
Also, how can I do the opposite: search within the comments only?
(I'm currently using Text Mate, but happy to change.)

See our Source Code Search Engine (SCSE). This tool indexes your code base using the langauge structure to guide the indexing; it can do so for many languages including JavaScript. Search queries are then stated in terms of abstract language tokens, e.g., to find identifiers involving the string "tax" multiplied by some constant, you'd write:
I=*tax* '*' N
This will search all indexed languages only for identifiers (in each language) following by a '*' token, followed by some kind of number. Because the tool understands language structure, it isn't confused by whitespace, formatting or interverning comments. Because it understands comments, you can search inside just comments (say, for authors):
C=*Author*
Given a query, the SCSE finds all the hits across the code base (possibly millions of lines), and offers these as set of choices; clicking on choice pulls up the file with the hit in the middle outlined where the match occurs.
If you insist on searching just raw text, the SCSE provides grep-style searches. If you have only a small set of files, this is still pretty fast. If you have a big set of files, this is a lot slower than language-structure based searches. In both cases, grep like searches get you more hits, usually at the cost of false positives (e.g., finding "tax" in a comment, or finding a variable named "Authorization_code"). But at least you have the choice.
While this doesn't operate from inside an editor, you can launch your editor (for most editors) on a file once you've found the hit you want.

Use ultraedit , It fully supports full text search ignoring comment or also within the comment search

How about NetBeans way (Find Symbol in the Navigate Menu),
It searches all variables,functions,objects etc.
Or you could customize JSLint and customize it if you want to integrate it in a web application or something like that.

I personnaly use Notepad++ wich is a great free code editor. It seems you need an editor supporting regular expression search (in one or many files). If you know Reg you can use powerfull search like in/out javascript comments...the work will be to build the right expression and test it with one file with all differents cases to be sure it will not miss things during real search, or maybe you can google for 'javascript comments regular expression' or something like...
Then must have a look at Notepad++ plugins, one is 'RegEx Helper' wich helps for building regular expressions.

Add spell check to my website

I have an asp-based website which I would like to add spell checking capabilities to the textarea elements on the page. Most of the pages are generated from an engine, though I can add JavaScript to them. So my preferred solution is a JavaScript-based one. I have tried JavaScriptSpellCheck and it works okay, though I would like to see what some of my other options may be. I also found spellchecker.net but at $3500 for a server license it seems excessive.
Spell checking can be in a separate window and must support multiple languages (the more the better). Ultimately I would like to send the spell check object a collection or delimited string of textarea names or id's (preferably names as they already exist in the pages) and have it spell check all of them, updating the text as spelling is corrected.

Check out using Google's api for this: http://www.asp101.com/articles/jeremy/googlespell/default.asp

Here is a free, open source Javascript library for spell checking that I authored:
https://github.com/LPology/Javascript-PHP-Spell-Checker
There's a link to a live demo at the top. It's designed to have the feel of a spell checker in a desktop word processor. I wrote it after being dissatisified with these same options.
To use, just include the JS and CSS files into your page, and then add this:
var checker = new sc.SpellChecker(
button: 'spellcheck_button', // opens the spell checker when clicked
textInput: 'text_box', // HTML field containing the text to spell check
action: '/spellcheck.php' // URL of the server side script
);
It includes a PHP script for spell checking, but it could be ported to another language fairly easily as long as it returns the correct JSON response.

If I were you, I'd look into something like aspell - this is used as one of the supported spellchecking backends in TinyMCE. Personally, I use pspell because it's integrated into PHP.
EDIT
There's an aspell integration here that has a PHP or a Perl/CGI version; might be worth checking out.

If I am not wrong, Firefox's English dictionary for spell checking takes around 800KB of data.
If you like to do everything in JavaScript -- for a full-featured spell checking engine, it means you need to load that 800KB data in every page load. It's really not a good idea.
So, instead of doing that in JavaScript, send the data to the server with AJAX, check it server side, and return it back; that's the best way.

Well this is quite old question, but my answer might help people who are looking for latest options on this question.
"JavaScript SpellCheck" is the industry leading spellchecker plugin for javascript. It allows the developer to easily add and control spellchecking in almost any HTML environment. You can install it in about 5 minutes by copying a folder into your website.
http://www.javascriptspellcheck.com/
Also support multiple languages - http://www.javascriptspellcheck.com/Internationalization_Demo

I might be a bit late on the answer to this question. I found a solution a long while ago. You must have a spell checker installed on your browser first. Then create a bookmark with the following code as the link.
javascript:document.body.contentEditable='true'; document.designMode='on'; void 0