function swapDisplay(div1, div2) {
	if(document.getElementById(div2).className=='hidden') {
		document.getElementById(div1).className = 'hidden';
		document.getElementById(div2).className = '';
	} else {
		document.getElementById(div1).className = '';
		document.getElementById(div2).className = 'hidden';
	}
}

function addLoadEvent(func) {
	var oldonload = window.onload;
	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			if (oldonload) {
				oldonload();
			}
			func();
		}
	}
}

addLoadEvent(function() { add_print_link('nav') });

function add_print_link(id) {
	if ( !document.getElementById || !document.getElementById(id) ) return;

	// add extra functions to page tools list
	var print_page = document.getElementById(id);

	// create print link
	var print_function = document.createElement('p');
	print_function.className = 'print-link';
	print_function.onclick = function() { print_preview(); return false; };
	print_function.appendChild(document.createTextNode('Print the Page'));
}

function print_preview() {
	// Switch the stylesheet
	setActiveStyleSheet('Print Preview');
	
	// Create preview message
	add_preview_message();

	// Print the page
	window.print();
}

function add_preview_message() {
var main_content = document.getElementById('content');
var main_body = main_content.parentNode;

	if (document.getElementById) {
		
		var preview_message = document.createElement('div');
		preview_message.id = 'preview-message';
	
		// Create Heading
		var preview_header = document.createElement('h3');
		var preview_header_text = document.createTextNode('This is a print preview of this page');
		preview_header.appendChild(preview_header_text);
		
		// Create paragraph
		var preview_para = document.createElement('p');
		var preview_para_text = document.createTextNode('Without this message of course.');
		
		var cancel_function_link = document.createElement('a');
		cancel_function_link.onclick = function(){ cancel_print_preview(); return false; };
		cancel_function_link.setAttribute('href', '#');	
		var cancel_function_link_text = document.createTextNode('Return to the existing page.');
		cancel_function_link.appendChild(cancel_function_link_text);
		preview_para.appendChild(preview_para_text); //
		preview_para.appendChild(cancel_function_link);
		
		// Put it all toegether
		preview_message.appendChild(preview_header); 
		preview_message.appendChild(preview_para);
		main_body.insertBefore(preview_message, main_content);
	}
}

function cancel_print_preview() {
	// Destroy the preview message
	var print_preview = document.getElementById('preview-message');
	var main_body = print_preview.parentNode;
	main_body.removeChild(print_preview);
	
	// Switch back stylesheet
	setActiveStyleSheet('default');
}

function setActiveStyleSheet(title) {
	var i, a, main;
	for (i=0; (a = document.getElementsByTagName("link")[i]); i++) {
		if(a.getAttribute("rel").indexOf("style") != -1
			&& a.getAttribute("title")) {
			a.disabled = true;
			if (a.getAttribute("title") == title) a.disabled = false;
		}
	}
}