[Javascript] Javascript arrays

[David Lovering]

A postscript to my earlier remark:

I should mention a peculiarity of IE regarding handlers -- the average
handler doesn't work very reliably when the object's contents are changed by
script, UNLESS (!!!) the script itself fires the onChange event at the
completion of its update.

// myList changes ... //

document.form["myForm"].myList.onChange();

Just thought you'd like to know.

-- Dave Lovering

----- Original Message ----- 
From: "David Lovering" <dlovering at gazos.com>
To: "[JavaScript List]" <javascript at LaTech.edu>
Sent: Thursday, May 06, 2004 6:55 AM
Subject: Re: [Javascript] Javascript arrays


> First off, I'd check to see if an element in the object list even has an
> attribute 'backgroundColor' before doing a comparison of its value to any
> set quantity.
>
> Secondly, unless I'm much mistaken 'browseform' is not a W3C accepted
> operator, so in all likelihood the lines that reference it will go
spinning
> down the drain.  [Of course, if you explicitly have a definition for it
> previous to its use of the style
>
>     var browseform = ....
>
> then everything might still be ok].  Lastly, it looks as though you intend
> to scan the entire contents of your list (delimeter-separated concatenated
> string?) for one or more values.  You should probably declare a working
> array thusly
>
>     var myArray = new Array();
>
> And then use "split" or some other construct to parse the content of the
> hidden field to fill the array.  Of course, I may be reading this whole
> thing wrong, but without the HTML constructs to which your functions point
> I'm not sure I'm getting the point of the whole exercise.
>
> Also, you may be doing this the hard way.  If you use the 'onChange' event
> handler method, you can tell immediately when a variable (even a hidden
one)
> has changed state, and can then write code to evaluate the context of the
> change only when it is strictly applicable.  When dealing with arrays, it
is
> sometimes helpful to keep a 'prior copy' of the array and do a diff of it
> against the 'new' value (assuming only one entry changes), thereby saving
> you the hassle of scanning each entry for inclusion/exclusion changes.
Then
> when you actually change the list, roll the now-different list back into
the
> 'prior' one in order to act as a reference for the next diff.
>
> I'd guess my final suggestion is to "show us the code" making up the
objects
> you wish to manipulate, and then we'll be working from a stronger
position.
>
> -- Dave Lovering
> ----- Original Message ----- 
> From: "Terry Riegel" <riegel at clearimageonline.com>
> To: "[JavaScript List]" <javascript at LaTech.edu>
> Sent: Thursday, May 06, 2004 4:30 AM
> Subject: [Javascript] Javascript arrays
>
>
> > Hello,
> >
> > I am new to javascript and would like to convert my code from a brute
> > force method to a simpler method. I hope someone can help me out.
> >
> > First let me say I am very inexperienced in Javascript, not
> > programming. So consequently I can understand concepts pretty well, but
> > struggle with the simple syntax issues.
> >
> > Here is part of the function:
> >
> > function changedest(dest,type)
> > {
> >    var td = document.getElementById(dest);
> >    if (td.style.backgroundColor == '#BFD7FF')
> >     {
> >       td.style.backgroundColor = '#FFFFFF';
> >       document.browseform["fm_list"].value =
> > document.browseform["fm_list"].value.replace("|"+dest,"");
> >     }
> >    else
> >     {
> >       td.style.backgroundColor = '#BFD7FF';
> >       document.browseform["fm_list"].value =
> > document.browseform["fm_list"].value+"|"+dest;
> >     }
> > }
> >
> >
> > The hidden field will contain the list of selected items like and gets
> > updated when a user clicks on a link if its in the list it gets
> > removed, if not it gets added. The problem is I am using the background
> > color to determine the status of the list, and there are situatiuons
> > when the background color and the list are out of sync. I would like to
> > create a way for the background color to be set from the list, but I
> > have no idea how to proceed. I have created a deselect() function, but
> > it is very crude. Here it is.
> >
> > function deselect()
> > {
> > var td = document.getElementById('.TEMP');
> > td.style.backgroundColor = '#ffffff';
> > var td = document.getElementById('app');
> > td.style.backgroundColor = '#ffffff';
> > var td = document.getElementById('apps');
> > td.style.backgroundColor = '#ffffff';
> > etc...
> > }
> >
> >
> > Thanks for any help with this.
> >
> > Terry Riegel
> >
> > _______________________________________________
> > Javascript mailing list
> > Javascript at LaTech.edu
> > https://lists.LaTech.edu/mailman/listinfo/javascript
> >
>
>
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