Mouseover Control
Webace supports graphics views of acedb data in two ways. These are
(1) with mouseover on, where holding the mouse over any clickable
object will display information about it in the status display and (2) with
mouseover off, where no information is displayed. The objects
on the display are always clickable regardless of the display mode.
Ideally displays would always with mouseover on, however there
is an overhead for each clickable object being the information which
must be transmitted over the network and interpreted by the users
browser. The system therefore automatically switches from
mouseover on to mouseover off mode as the number of
clickable objects on a display passes a particular threashold. The
optimal threashold will vary according to the network connection and
the power of the computer the browser is being run on, so this is a
configurable parameter [mouseover regions]. Select configure to set this. The default value is 400
regions. You can also disable mouseover mode at any time by
deselecting it from the listbox (it is turned on by default).
Java v JavaScript
The mouseover display functionality is provided through either
a java applet or embedded javascript. The two systems provide similar
functionality, however each will not work on some browers, so both are
provided to support the largest number of users. Webace attempts to
autoconfigure itself by trying to identify your browser the first time
you connect to it, however you can also manually set the
configuration. If your browser supports both java and javascript,
your choice may be influenced by other factors - on some
machine/browser combinations one option my be faster. At present java
mouseover displays do not support labelling or dna clicking, whereas
they do implement 'shift click' to highlight objects rather than show
them when just clicking. Javascript is also used to implement window
control in most parts of webace, so if your browser does not support
javascript 1.1, most actions will overwrite the contents of a netscape
window rather than loading into another one.
15/3/98, webace@sanger.ac.uk