// JavaScript Document
var randomnumber=Math.floor(Math.random()*4) + 1;
var currentMain = randomnumber;
var firstRun = true;
var myinterval;

if (document.images) 
{
   main1 = new Image();
   main2 = new Image();
   main3 = new Image();
   main4 = new Image();
   main1.src = "images/main_1.gif";
   main2.src = "images/main_2.gif";
   main3.src = "images/main_3.gif";
   main4.src = "images/main_4.gif";
}

function showMain(mainID)
{
	if(mainID == "next") {
		document.getElementById("main_" + currentMain).style.display = "none";
			if(currentMain == 4) {
				currentMain = 1;
			} else {
				currentMain++;
			}
		document.getElementById("main_" + currentMain).style.display = "block";
		if(firstRun == true) {
			firstRun = false;
		} else {
			clearInterval(myinterval);
		}
		
	} else if(mainID == 1 || mainID == 2 || mainID == 3 || mainID == 4) {
		document.getElementById("main_1").style.display = "none";
		document.getElementById("main_2").style.display = "none";
		document.getElementById("main_3").style.display = "none";
		document.getElementById("main_4").style.display = "none";
		
		document.getElementById("main_" + mainID).style.display = "block";
		currentMain = mainID;
		if(firstRun == true) {
			firstRun = false;
		} else {
			clearInterval(myinterval);
		}
	}
}


function showNextMain() {
	firstRun = true;
	showMain("next");
}

myinterval = setInterval("showNextMain()",7000);