Forcing cursor to remain visible?

[Christopher Finke]

I am writing a Web-based text editor that will be used mainly for
editing code. To facilitate this task, whenever the Enter button is
pressed within the textarea, the event is caught and the next line is
automatically tabbed to match the previous line. However, because I
have caught the event and manually inserted the line feed along with
the appropriate number of tabs, the textarea doesn't scroll
automatically if the line feed puts the cursor below the last line
visible on the textarea.

Is there any way to force the cursor to remain visible in this
situation?

Chris Finke

 

[RobG]

I am writing a Web-based text editor that will be used mainly for
editing code. To facilitate this task, whenever the Enter button is
pressed within the textarea, the event is caught and the next line is
automatically tabbed to match the previous line. However, because I
have caught the event and manually inserted the line feed along with
the appropriate number of tabs, the textarea doesn't scroll
automatically if the line feed puts the cursor below the last line
visible on the textarea.

Is there any way to force the cursor to remain visible in this
situation?

Use scrollTop (non-standard, DOM 0, but widely supported), something like:

taRef.scrollTop && taRef.scrollTop += 16;

 

[RobG]

Use scrollTop (non-standard, DOM 0, but widely supported), something like:

taRef.scrollTop && taRef.scrollTop += 16;

Ooops, that's crap, eh? Added the 'taRef.scrollTop && ' quickly before
posting. Try:

('number' == typeof x.scrollTop) && (x.scrollTop += 16);

 

[Christopher Finke]

Try: ('number' == typeof x.scrollTop) && (x.scrollTop += 16);

I had thought of this, but this will scroll the textarea whether or not
it would have scrolled in the first place. If I use this method, I'd
need a way to determine if the cursor is currently visible in the
textarea. Also, wouldn't the 16 only apply for a certain font size?

Chris

 

[RobG]

I had thought of this, but this will scroll the textarea whether or not
it would have scrolled in the first place.
Yes.


If I use this method, I'd
need a way to determine if the cursor is currently visible in the
textarea.

Yes, as far as I know a textarea doesn't provide anything that will let
you know that. I can think of a number of ways to do it, but they all
are really hackish. If this is for code, why not copy the text into a
text editor (see below)?

Also, wouldn't the 16 only apply for a certain font size?

Yes. scrollTop is in pixels, so that's all you have. Have you
considered using some element other than a textarea? Unfortunately I
think all the alternatives are browser-specific.


Mozilla: designMode
<URL:http://developer.mozilla.org/en/docs/Rich-Text_Editing_in_Mozilla>

IE: contentEditable
<URL:http://msdn.microsoft.com/workshop/author/dhtml/reference/properties/contenteditable.asp>

mozex: edit textarea content in your choice of text editor:
<URL:http://mozex.mozdev.org/>

There's some helpful stuff here:
<URL:http://ifindkarma.typepad.com/relax/2005/01/life_in_a_texta.html>


Go nuts...