function changeFontSize(adjustment){
	changeFontSizeForClass("broodtekst",adjustment);
	changeFontSizeForClass("titel",adjustment);
}

function changeFontSizeForClass(className, adjustment){
	var elms = getElementsByClass(className);
	for(var i=0;i<elms.length;i++){
		var elm = elms[i];
		elm.style.fontSize = ((elm.style.fontSize?parseInt(elm.style.fontSize):12) + adjustment) + "px";

	}
}

function getElementsByClass( searchClass, domNode, tagName) {
	if (domNode == null) domNode = document;
	if (tagName == null) tagName = '*';
	var el = new Array();
	var tags = domNode.getElementsByTagName(tagName);
	var tcl = " "+searchClass+" ";
	for(i=0,j=0; i<tags.length; i++) {
		var test = " " + tags[i].className + " ";
		if (test.indexOf(tcl) != -1)
			el[j++] = tags[i];
	}
	return el;
}