// JavaScript for textbook home page

window.onload=function(){
	if( 'function' == typeof window.styleFormElements ) styleFormElements();
	if( 'function' == typeof window.makeDivsCollapsible ) makeDivsCollapsible();
	if( 'function' == typeof window.initOverLabels ) initOverLabels();
}

function makeDivsCollapsible() {
	var boxes = getElementsByClassName('DIV','formbox');
	for( i=0; i<boxes.length; i++ ) {
		var header = boxes[i].getElementsByTagName('H3')[0];
		addEvent(header,'click',toggleDiv);
		if( elementHasClassName(boxes[i],'closed-if-js') ) {
			var fieldset = boxes[i].getElementsByTagName('FIELDSET')[0];
			addClassName(boxes[i],'closed');
		}
		else {
			addClassName(boxes[i],'open');
		}
	}
}

function toggleDiv(evt) {
	if (!evt) evt = window.evt // for IE/Win
	var node = findEventOwner(evt);	
	var div = node.parentNode;
	if( elementHasClassName(div,'closed') ) {
		removeClassName(div,'closed');
		addClassName(div,'open');
	}
	else {
		removeClassName(div,'open');
		addClassName(div,'closed');
	}
}