function updateCal(month, year) {
	var xmlHttp = createXML();
	
	xmlHttp.open('GET', 'cal.php?m=' + month + '&y=' + year, true);
	xmlHttp.onreadystatechange = function(){
		if(xmlHttp.readyState == 4 && xmlHttp.status == 200){
			document.getElementById('cal').innerHTML = xmlHttp.responseText;
		}
	}
	xmlHttp.send(null);
}

function controlForm(){
	
	if ( document.getElementById('name').value == '' ) {
		alert ( "Je hebt geen naam ingevuld." );
		return false;
	}
	
	if ( document.getElementById('message').value == '' ) {
		alert ( "Je hebt geen bericht ingevuld." );
		return false;
	}
	
	return true;
	
}

 function ins(target, text) {
 	      var obj = document.getElementById(target);
 	      var actual = tmp = obj.value.replace(/\r\n/g, "\n");
        if(document.selection) {
            obj.focus();
            var orig = obj.value.replace(/\r\n/g, "\n");
            var range = document.selection.createRange();
 
            if(range.parentElement() != obj) {
                return false;
            }
 
            range.text = text;
            
            
 
            for(var diff = 0; diff < orig.length; diff++) {
                if(orig.charAt(diff) != actual.charAt(diff)) break;
            }
 
            for(var index = 0, start = 0; 
                tmp.match(text) 
                    && (tmp = tmp.replace(text, "")) 
                    && index <= diff; 
                index = start + text.length
            ) {
                start = actual.indexOf(text, index);
            }
        } else if(obj.selectionStart) {
            var start = obj.selectionStart;
            var end   = obj.selectionEnd;
 
            obj.value = obj.value.substr(0, start) 
                + text 
                + obj.value.substr(end, obj.value.length);
        }
        
        if(start != null) {
            setCaretTo(obj, actual.indexOf(text, index) + text.length /2 );
        } else {
            obj.value += text;
        }
    }
    
 
    function setCaretTo(obj, pos) {
        if(obj.createTextRange) {
            var range = obj.createTextRange();
            range.move('character', pos);
            range.select();
        } else if(obj.selectionStart) {
            obj.focus();
            obj.setSelectionRange(pos, pos);
        }
    }