ok, habs schon gelöst:
document.onkeydown = function(e)
{
// get event object for IE
if(!e) var e = window.event;
// F1 == 112
if(e.keyCode == 112)
{
alert("hilfe");
// prevent default behaviour (open the browser help)
return false;
}
};
window.onhelp = function()
{
// prevents opening the IE browser help
return false;
}