//here you place the ids of every element you want.
var ids=new Array('a1','a2','a3','thiscanbeanything');

function switchid(id){	
	hideallids();
	showdiv(id);
}

function showhide(id){
	if (document.getElementById) { // DOM3 = IE5, NS6
	    if(document.getElementById(id).style.display == 'none'){
	        showdiv(id);
	    }else{
            hidediv(id);
	    }
		
	}
	else {
		if(document.id.display == 'none'){
	        showdiv(id);
	    }else{
	        hidediv(id);
	    }
    }
}

function hideallids(){
	//loop through the array and hide each element by id
	for (var i=0;i<ids.length;i++){
		hidediv(ids[i]);
	}		  
}

function hidediv(id) {
	//safe function to hide an element with a specified id
	if (document.getElementById) { // DOM3 = IE5, NS6
		document.getElementById(id).style.display = 'none';
	}
	else {
		if (document.layers) { // Netscape 4
			document.id.display = 'none';
		}
		else { // IE 4
			document.all.id.style.display = 'none';
		}
	}
}

function showdiv(id) {
	//safe function to show an element with a specified id
		  
	if (document.getElementById) { // DOM3 = IE5, NS6
		document.getElementById(id).style.display = 'block';
	}
	else {
		if (document.layers) { // Netscape 4
			document.id.display = 'block';
		}
		else { // IE 4
			document.all.id.style.display = 'block';
		}
	}
}

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);
}