/*

	UW-Madison Graduate School Home Page
	JS functions for switching menu tabs
	and cookie functionality
	
	(c)2006 Yoh Suzuki and Keaton Miller
	
	Last revised March 2007

*/

function toggle(which) {
	if(which <= 4) {
		/*turnON(which);
		turnOFF((which)%4 + 1);
		turnOFF((which+1)%4 + 1);
		turnOFF((which+2)%4 + 1);*/
		turnOFF(1);
		turnOFF(2);
		turnOFF(3);
		turnOFF(4);
		turnON(which);
		setTabCookie(which);
	}
}

function setTabCookie(which) {
	createCookie('menuTab', which, 0);
}

function getTabCookie() {
	var result = readCookie('menuTab');
	if (result) {
       toggle(result);
     } else {
       toggle(2);
     }
}

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 var 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 eraseCookie(name) {
	createCookie(name,"",-1);
}

function turnON(which) {
	if(which <= 4) {
		e = document.getElementById("tab"+which);
		if(e.className == "")
			e.className += "selected";
		e = document.getElementById("tab"+which+"menu");
		if(e.className == "menu")
			e.className += " selected";
	}
	else {
		e = document.getElementById("tab"+which);
		if(e.className == "news")
			e.className += " selected";
		if(e.className == "news researchnews")
		     e.className += " selected";
	}
}

function turnOFF(which) {
	if(which <= 4) {
		e = document.getElementById("tab"+which);
		if(e.className == "selected")
			e.className = e.className.replace(new RegExp("selected\\b"), "");
		e = document.getElementById("tab"+which+"menu");
		if(e.className == "menu selected")
			e.className = e.className.replace(new RegExp(" selected\\b"), "");
	}
	else {
		e = document.getElementById("tab"+which);
		if(e.className == "news selected")
			e.className = e.className.replace(new RegExp(" selected\\b"), "");
		if(e.className == "news researchnews selected")
          	e.className = e.className.replace(new RegExp(" selected\\b"), "");
	}
}