var number_of_projects = 18;

function get_random(num)
{
    if(num == 0) {
        num = 1;
    }
    var ranNum= Math.round(Math.random()*num);
    return ranNum;
}

function reset() {
	hide("chair_msg");
	hide("project_banner");
	for(var i=1;i<=11;i++) {
		hide(i);
	}
	hide("sponsors");
	hide("sponsor_banner");
	hide("faculty_banner");
	hide("faculty");
	hide("bottom");
}
function showProjects() {
	reset();
	for(var i=1;i<=number_of_projects;i++) {
		show(i);
	}
	show("project_banner");
}

function showSponsors() {
	reset();
	show("sponsors");
	show("sponsor_banner");
}

function showFaculty() {
	reset();
	show("faculty_banner");
	show("faculty");
}

function showMain() {
	init();	
}

function hide(divId) {
    list = document.getElementsByTagName("div");
    for(i = 0;i<list.length;i++)
    {
        if(list.item(i).id == divId)
        {
		list.item(i).style.display = "none";
	}
    }
}

function show(divId) {
    list = document.getElementsByTagName("div");
    for(i = 0;i<list.length;i++)
    {
        if(list.item(i).id == divId)
        {
		list.item(i).style.display = "";
	}
    }
}

function init() {
    reset();
    show("chair_msg");
    show("project_banner");
    show("bottom");
    list = document.getElementsByTagName("div");
    var first = get_random(number_of_projects);
    var second = get_random(number_of_projects);
    
    while(first == 0 || second == 0) {
    	first = get_random(number_of_projects);
    	second = get_random(number_of_projects);
    }
    while (first == second) {
    	second = get_random(number_of_projects);
    }
    var i = 0;
    for(;i<list.length;i++)
    {
    	if(list.item(i).id > 0 && list.item(i).id <= number_of_projects)
    	{
	    if(list.item(i).id == first || list.item(i).id == second) {
		list.item(i).style.display = "";
	    }
	    else {
		list.item(i).style.display = "none";
	    }
	}
    }
}