Contolling Status Bar Message

I am trying to control what gets displayed on the status bar of my site.onMouseOver and onMouseOut event handlers displays the right message i.e:

Code:
onMouseOver="window.status='http://www.mysite.com/index.html' return true"
onMouseOut="window.status=''return true"
But when I add onMouseDown,it does not works.i.e.

Code:
onMouseDown="window.status='http://www.mysite.com/index.html' return true"
Can someone please tell me how to make this work???
And how to control the status bar message when the site initially loads up.