jQuery Forum

Just to be clear, it is the CSS pseudo class I want to trigger
a:hover { /* some CSS */ }
without needing to know what is in the CSS block.

Unfortunately it's not possible to trigger pseudo-selectors like that.
The common way of achieving what you describe would be to add a class
selector to your CSS and toggle the class on and off for the element
you want to show hover styles for. Like this:
.hoverClass { /* some CSS */ }
$('#triggeringElement').hover(
function(){
$('#targetElement').toggleClass('hoverClass');
},
function(){
$('#targetElement').toggleClass('hoverClass');
}
);
Joel.