document.onkeydown = navigateThrough;
var key2id = new Array( 'prevLink','upLink','nextLink','downLink' );

function navigateThrough( event ) {
	if ( window.event ) event = window.event;
	if ( !event.ctrlKey ) return;
	var link = null;
	if ( !(key = (event.keyCode ? event.keyCode : (event.which ? event.which : null)))) return;
	link = document.getElementById( key2id[key-0x25] );
	if (link && link.href) document.location = link.href;
}