function registerChange(elm) {
	var n=0;
	document.getElementById('jobarea').length=0;
	if (elm.selectedIndex !== false) {
	    document.getElementById('jobarea').disabled=false;
	    for(i=0; i<document.getElementById('jobarea').length; i++) {
	        document.getElementById('jobarea')[i] = null;
	    }
		for(i=0; i<elm.options.length; i++) {
	 		if (elm.options[i].selected == true) {
				var thisValue = elm.options[i].value;
			    document.getElementById('jobarea')[n] = new Option(elm.options[i].text, 'false', true);
			    document.getElementById('jobarea')[n].style.backgroundColor = '#c0c0c0';
			    n++;
			    for(c=0; c<(options[thisValue].length); c++) {
			        document.getElementById('jobarea')[(n)] = new Option(titles[thisValue][c], options[thisValue][c], false);
			        n++;
			    }
			}
		}
	} else {
	    document.getElementById('jobarea').disabled=true;
	    for(i=0; i<document.getElementById('jobarea').length; i++) {
	        document.getElementById('jobarea')[i] = false;
	    }
	    document.getElementById('jobarea')[0] = new Option('Vælg først jobkategori', 'false', true);
	}
}