Re: Re: Determining number of visible OPTIONs in a SELECT

For anyone who's interested, here's what I did.  The following code
has to run after the body exists.  Also, ListViewer is the class I'm
using to manage paging the data, so I store the height of one option
in ListViewer._optionHeight.

The project I'm working on only supports IE and Mozilla, so I
unfortunately don't have the time or resources to test in Opera,
Safari, or Konqueror, but it seems to work in IE and Mozilla.

Anyway, here's the code:

// this anonymous function makes an attempt at figuring out how tall an
// OPTION element is.  We use the result when computing the optimum page
// size in the auto-page-size calculation.
(function() {
    var select = document.createElement('select');
    var option = document.createElement('option');

    select.size = 1;
    select.style.border = 'none';
    select.style.visibility = 'hidden';

    document.body.appendChild(select);

    // store the clientHeight _before_ we put the option inside the select
    // because otherwise Mozilla goes kinda wonky....
    ListViewer._optionHeight = select.clientHeight;

    select.appendChild(option);

    // detect IE...
    if(!option.offsetHeight) {
        // This -= 6 is a magic number determined by trial and error to fix
        // IE.  I can't explain why it's 6 and not some other number.  It
        // might be different from 6 in a different version of Windows or
        // IE, or with a different theme.  Setting the font size to Extra
        // Large did not affect it, and choosing one of the high-contrast
        // themes did not affect it.  Six seems like a good approximation
        // for now.
        ListViewer._optionHeight -= 6;
    }

    select.removeChild(option);
    document.body.removeChild(select);

    // we probably don't need to do this, but I _really_ don't want to leak
    // memory...
    option = null;
    select = null;
})();


Thanks for the suggestions,

Ian

--
Tired of pop-ups, security holes, and spyware?
Try Firefox: http://www.getfirefox.com


------------------------ Yahoo! Groups Sponsor --------------------~--> 
Get fast access to your favorite Yahoo! Groups. Make Yahoo! your home page
http://us.click.yahoo.com/dpRU5A/wUILAA/yQLSAA/9rHolB/TM
--------------------------------------------------------------------~-> 

Unsubscribe
[email protected]

List info
http://www.quirksmode.org/dom/list.html 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/wdf-dom/

<*> To unsubscribe from this group, send an email to:
    [email protected]

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/