[jQuery] using functions as extensions - why does FF not take it?

[jQuery] using functions as extensions - why does FF not take it?


has anyone had the following problem before?
VERSION 1 =================// works in IE and FF
myFunction(){
...
}
document.onmousedown=myFunction;
VERSION 2 =================// works in IE but not in FF
jQuery.fn.extend({
myFunction: function() {
...
}
});
$(document).mousedown(function(){
$().myFunction();
});