function revlookup(r,v,s) {
	for (j=s;j<r.length;j++) {
		if (r[j].value==v) return j;
	}
}

function checkall(x,l) {
        elRef = document.forms['tidning'].elements[x];
        t=0;
        for (i=0;i<l.length;i++) {
        				t=revlookup(elRef,l[i],t);
        				elRef[t].checked = true;
        }
}
function clearall(x,l) {
        elRef = document.forms['tidning'].elements[x];
        t=0;
        for (i=0;i<l.length;i++) {
        				t=revlookup(elRef,l[i],t);
        				elRef[t].checked = false;
        }
}
function inverseall(x,l) {
        elRef = document.forms['tidning'].elements[x];
        t=0;
        for (i=0;i<l.length;i++) {
        				t=revlookup(elRef,l[i],t);
        				ref=elRef[t];
        				ref.checked=!ref.checked;
        }
}