/* NRCS global functions */


function setSearchBox() {	
	// Initialize search box design enhancements

	if (document.forms.search) {

		// Find submit button in DOM (last input tag in form - no ID set in HTML)
		var searchNodes = document.forms["search"].getElementsByTagName("input");
		var searchButton = searchNodes.item(searchNodes.length - 1);

		if (searchButton.getAttribute("type") == "image") {
			// Get current image path and filename
			var goImagePath = searchButton.src;
			var goImage = goImagePath.substr(goImagePath.lastIndexOf("/") + 1);
	
			// Preload images (swap filenames to keep correct path)
			var searchOut = new Image();
			searchOut.src = goImagePath;
			var searchOver = new Image();
			searchOver.src = goImagePath.replace(new RegExp(goImage, "i"), "button_go_over.gif");

			// Set functions
			searchButton.onmouseover = function() { this.src = searchOver.src; }
			searchButton.onfocus = function() { this.src = searchOver.src; }
			searchButton.onmouseout = function() { this.src = searchOut.src; }
			searchButton.onblur = function() { this.src = searchOut.src; }
		}

		// Clear search box
		document.getElementById('searchTerms').onfocus = function() { if (this.value == "Enter Keywords") this.value = ""; }
	}
}



// Style Switcher functions
// For details, refer to http://www.alistapart.com/stories/alternate/

function setActiveStyleSheet(title) {
	var i, a, main;
	if (document.getElementsByTagName) {
		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;
			}
		}
	}
}

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

function getPreferredStyleSheet() {
	var i, a;
	if (document.getElementsByTagName) {
		for(i=0; (a = document.getElementsByTagName("link")[i]); i++) {
			if(a.getAttribute("rel").indexOf("style") != -1
			&& a.getAttribute("rel").indexOf("alt") == -1
			&& a.getAttribute("title")
			) return a.getAttribute("title");
		}
		return null;
	}
}

function createCookie(name,value,days) {
	if (days) {
		var date = new Date();
		date.setTime(date.getTime()+(days*24*60*60*1000));
		var expires = "; expires="+date.toGMTString();
	}
	else expires = "";
	document.cookie = name+"="+value+expires+"; path=/";
}

function readCookie(name) {
	var nameEQ = name + "=";
	var ca = document.cookie.split(';');
	for(var i=0;i < ca.length;i++) {
		var c = ca[i];
		while (c.charAt(0)==' ') c = c.substring(1,c.length);
			if (c.indexOf(nameEQ) == 0) return c.substring(nameEQ.length,c.length);
	}
	return null;
}


function addEvent(obj, evType, fn) {
	// Add function to any event handler

	if (obj.addEventListener) {
		obj.addEventListener(evType, fn, true);
		return true;
	} else if (obj.attachEvent) {
		var r = obj.attachEvent("on" + evType, fn);
		return r;
	} else
		return false;
}

function loadPageCSS(e) {
	if (document.getElementsByTagName) {
		var cookie = readCookie("style");
		var title = cookie ? cookie : getPreferredStyleSheet();
		setActiveStyleSheet(title);
	}
}
function savePageCSS(e) {
	if (document.getElementsByTagName) {
		var title = getActiveStyleSheet();
		createCookie("style", title, 1);
	}
}




// Add onload and onunload functions
if (document.getElementsByTagName) {
	addEvent(window, 'load', loadPageCSS);
	addEvent(window, 'load', setSearchBox);
	addEvent(window, 'unload', savePageCSS);
}

var cookie = readCookie("style");
var title = cookie ? cookie : getPreferredStyleSheet();
setActiveStyleSheet(title);