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Re: [DHTML Style Guide] auto-complete widget proposal

From: Chris Blouch <cblouch@aol.com>
Date: Tue, 25 Mar 2008 15:44:51 -0400
Message-ID: <47E95633.8000904@aol.com>
To: Becky Gibson <Becky_Gibson@notesdev.ibm.com>
CC: wai-xtech@w3.org

Maybe this is implementation detail but should we qualify that the list 
of matching items (results) must be reasonably limited? If the list is 
allowed to grow to unbounded sizes, arrow navigation through the list 
will range from cumbersome to unusable. For example, if I type A and I'm 
in an autocomplete Google search box, the results list could be nearly 
infinite. I suspect there is some correlation between typical input 
length and auto-complete list length. If my typical input is 10 
characters then I'm probably willing to arrow down about 5 times before 
it doesn't become worth my while. For longer, more complex or harder to 
remember values the utility of auto-complete increases so I'd be willing 
to arrow down more. I would be far more interested in wading through a 
list of long email addresses to find one than to enter a search query 
for 'dogs' by typing d and doing a down arrow through a list.

CB

Becky Gibson wrote:
> My interpretation of an auto-complete widget is some type of a combo-box 
> where the choices offered are filtered by the information typed into the 
> box.  An editable auto-complete allows choices that are not in the list to 
> be entered. An example of an editable auto-complete is the URL field in 
> the browsers. 
>
> With focus in the textbox portion of the widget the user may:
> - Click in the empty text box or on an associated icon display the entire 
> list of choices in a drop-down. Most auto-complete widgets will have an 
> arrow or icon associated with the textbox.
>
> -press the up or down arrow or alt+down or alt+up arrow to display the 
> list of choices - focus remains in the textbox and no choice is 
> highlighted. Press the down arrow to highlight the first choice in the 
> list; press the up arrow to highlight the last choice in the list.  Press 
> the arrow keys to reach the desired choice in the list.  Or, move the 
> mouse pointer over and item in the list to highlight it. The highlighted 
> choice is displayed in the textbox.  Press enter or click on the 
> highlighted choice to select it.
>
> -type a letter. If any of the available choices begin with the letter 
> typed, those choices are displayed in a drop down.  Pressing the down 
> arrow highlights the first choice in the list, pressing the up arrow 
> highlights the last choice in the list.  The user may move the mouse 
> pointer over the items in the list to highlight a choice.  The highlighted 
> choice is displayed in the text box. The user presses enter or clicks on a 
> choice to select a highlighted choice.  Once a choice is selected (via 
> enter or mouse click) the drop down list of choices is closed and the 
> selected choice is displayed in the textbox. 
>
> -type several letters.  As the user types letters the list of choices is 
> filtered so that only those that begin with the typed letters are 
> displayed.  Until the user presses the arrow keys or uses the mouse 
> pointer to highlight a particular choice, only the typed letters are 
> displayed in the textbox. In an editable auto-complete, If there are no 
> choices that match the letter(s) typed, the drop down list of choices is 
> closed. In a non-editable auto-complete any letters which do not result in 
> a match from the list are ignored, the drop down list of choices remains 
> static until the user presses escape to clear the text field, backspaces 
> to remove some of the letters previously typed, or types an additional 
> letter that results in a valid list of choices.
>
> -press escape.  If there is no text in the textbox, pressing escape does 
> nothing.   With text in the textbox (either typed directly by the user or 
> via highlighting a choice from the drop down) pressing escape clears the 
> text in the textbox.  In an editable auto-complete, if the list of choices 
> was open, it is closed. For an auto-complete that is not editable, the 
> user must make some selection.  In this case pressing escape may display 
> the entire list of choices via the drop down, invoke an error, or return 
> the field to a default value (which could also be the behavior of an 
> editable auto-complete).
>  
>
> Becky Gibson
> Web Accessibility Architect
>                                                        
> IBM Emerging Internet Technologies
> 5 Technology Park Drive
> Westford, MA 01886
> Voice: 978 399-6101; t/l 333-6101
> Email: gibsonb@us.ibm.com
> blog: WebA11y
>
>
>   
Received on Tuesday, 25 March 2008 19:45:53 UTC

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