I need to write my own code editor in browser. I found CodeMirror but I don't understand how to do this. I need simple code.
Can I use textarea or something else? (for example content editable). How to underline, colorize, auto complete the code?
Please, give me some advice. I will be very grateful.
I've read a book from O'Reilly, Douglas Crockford, about JS so I've some basics.
Check the html behind a code editor example page. Use WebKit's (Safari/Chrome) "Inspect Element".
As you can see there is a large div over a textarea that holds individual strings, so the user just gets the "illusion" he is typing in a textarea. The textarea is still there but it is not what you really are seeing.
If you want syntactical coloring you will need lexicographic analysis of the string, which is usually done by a lexer that outputs tokens. These tokens are caught by a process that collects them in individual div's that have f.i. the same text color. Then that div overlays the textarea.
If you want to go deeper in the code you will also need semantic parsing and a lot of coffee to program all of that.
Good luck, do you know you're taking on something big? And why would you reinvent this, it's already been done superbly by others.
You might want to take a look at tinyMCE if uou haven't already.
Related
In the Visual Event description, it says that it extracts "which elements have events attached to them". I can confirm this by running the bookmarklet and seeing all the colour highlights.
I would like to extract this information without the fancy presentation so that I can play around with it into a script (Ruby/Python/Perl). In other words, I would like to get a list of the divs (and their info ideally) from Visual Event.
Is there any way to do this without digging through the code on GitHub? Not to say that I'm not willing to do this, I was just wondering if there was an easier way.
There is no way to accomplish this very oddly specific task without digging through the code, although this isn't as hard as it seems considering it's quite legible and easy to build on your own system, even if you don't have any previous experience with JavaScript.
Before I started to try and make this thing, I wanted to know if it is possible, under the following circumstances:
The code to script up that math must be able to be taken, submitted and stored in a database
The code for two pieces of math which look exactly the same must have the exact same code
According to the requirements, wherever the user clicks his or her mouse, the caret must move to that specific element or part of the math
So, is it possible? I'm looking forward to using technologies such as HTML, JavaScript, jQuery, and even Flash as a last resort.
MathQuill lets you type maths in a WYSIWYG fashion, source here.
There is a demo on the homepage.
I think you want something like MathML. Take a look here. http://www.w3.org/Math/
or maybe http://code.google.com/p/mathmleditor/
I found this a while ago http://www.codecogs.com/latex/eqneditor.php pretty useful implementation of LaTeX with a live preview, I've used it a few times. Probably doesn't fit the bill for your point 3 either but just in case it is useful.
I want to know how to make a text area in a browser into a programmers text editor.
For anyone that uses textmate -- I basically want it web-based.
for anyone that uses notepad++ -- same idea as above.
I know how to make a text area
using html.
what I dont know is how to tag the text areas.
for instance. in notepad++ and textmade, I can insert the <> tags and it will highlight the text blue.
How can I achieve this, live, in a browser.
I already know how to parse it after the text has been posted.
I want it to be parsed while the user is typing it.
EditArea is pretty good.
In addition to EditArea there's CodeMirror and Mozilla's Bespin
EDIT: I misunderstood the question a little. Jump to ORIGINAL ANSWER if you are curious.
EDIT2: My answer is how to provide SYNTAX HIGHLIGHTING (what is specified in the question itself). Highlighting individual characters unrelated to the syntax requires trivial javascript. This is also distinct from 'auto format' which is commonly interpreted to mean 'adjust my indent levels so it all looks good'.
This is a difficult task, but not as impossible as it seems. Once again, TextMate comes to our rescue but in a different fashion.
In TextMate, open the bundle editor and look at the language definition for HTML. Those are regexes that process the document and assign a 'scope' to each piece.
'Simply' parse that language definition format into the various components, and then use the regexes themselves like TextMate does to assign a scope/color. Piece of cake, right? :)
I would personally start with the most lightweight open source rich text editor you can find, then hack it into that. Or ya know, whatever floats your boat.
I hope that gave you some good ideas.
ORIGINAL ANSWER:
For Firefox, you can install the plugin 'It's All Text' from here:
https://addons.mozilla.org/en-US/firefox/addon/4125/
It works for me with 3.6.12. Set the path in preferences to TextMate (or whatever), and optionally set a hotkey or adjust the other settings to your liking. Be default, when your cursor is over a Textarea, a small button saying "Edit" will appear and open the contents of the Textarea in your editor. Saving will put the data back into the Textarea.
I hope this helps.
JSMinNpp plugin just for javascript auto-formatting
http://sourceforge.net/projects/jsminnpp/
by simple I mean, having buttons:
bold,
italic,
numbered list
bullet point list
indent left
indent right
spell check (obviously supported by ready made js component)
by custom I mean: having custom icons - so really just custom design
no frameworks, written from scratch, lightweight, compatible with major browsers
this is one of the main components of the webapp, so it has to be super lightweight, that's why I don't want frameworks
Unless you are targeting one browser, editors are immensely complicated components to get to work cross browser. There's no reason to do it yourself, unless you want to learn.
Use one of the many available that allow customization:
tinymce,
fckeditor,
wysihat,
others
Writing an editor that works cross-platform can be difficult, but, you should create your own framework as you do it, as it is a large project.
If you just want custom icons, that will depend on how long it takes you to make them, but, to get some basic functionality isn't that hard, probably less than 40 hrs of work if you know what you are doing.
In Unix writing your own shell used to be a rite of passage, in javascript it may be writing your own editor. :)
Where it gets tricky is if I have
<b>some text</b><i>more text</i>
and I decide to remove the tags from this text, then how to fix it will get tricky.
If you want to use only css then it gets to be more of a problem as you are grouping text from span tags, and fixing css classes, while the user is continuing to make changes.
I am dealing with this currently as I want an editor that works in XHTML2.0, and it is not a trivial issue, much harder than it is to do in a desktop application.
I would suggest getting it to work on Firefox 3 and Safari first, then, once it is working, go back and add in the code to get it to work on IE8, and if you want IE7, since MS is pushing IE8 out as a critical update now.
Don't.
Go get something else (any of those Jason mentioned, or e.g. what SO itself uses, WMD). Swap out its images. The end.
Seriously you don't want to write your own editor unless you have a very good reason for it functionally, not just what it looks like.
Read through the first chapters of the emacs tutorial, and you will see that there is not anything like a "simple" editor. But google will give you lots of easy customizable editors.
I am aware that Javascript WYSIWYG editors use the inbuilt editor mode of the browser to function, but that comes up with various problems and issues.
Can an editor be built from scratch in JS, something like what Buzzword people have done with flash/flex? I came across this blog post recently and I am just wondering if this can be built (atleast to a moderate extent) using Javascript?
It depends what you mean by "from scratch". Google Docs provides a pretty good text editor in JS. Is that what you mean ?
Of course you can do it and it is not very difficult.
But before reinventing the wheel please take a look at all the existing ones.
Many of them are really very well written and open source.
Almost anything can be done with JavaScript. You have the basic building tools right there - you can intercept all mouse events and nearly all keyboard events. You can use a GIF animation for simulating the caret. The trickier part might be measuring the size of text so that you can position your caret where you need to. I'm not exactly sure how you could do that. But if you figure that out, the rest is doable. Although it will really require tons of wheel-reinventing code.
Reminds me of a little experiment I did sometime back... I basically tried to create a primitive editor by simply listening to keypresses on a DIV and to insert them into the DIV as a new node. So imagine, each character would be wrapped in a tag! It actually worked. But, once it reaches a couple of paragraphs, node insertion and deletion becomes rather slow. You will type a character, and it would only appear after a slight delay, and this simply unacceptable, and eventually I just gave up. Anyway it was just a random thing I wanted to try out..
Coming back to your question, I wonder if this can be replicated in JS alone as frankly the flash has superior raw processing power compared to JS. Even if it's technically feasible, I doubt whether it will be fast enough to actually work well. My two cents!
Atwood's Law:
Any application that can be written in JavaScript, will eventually be
written in JavaScript.