function navigation(which_nav)
{
var which_nav = which_nav;
var a = document.getElementById("courses_navigation");
var b = document.getElementById("resources_navigation");
var c = document.getElementById("courses_img");
var d = document.getElementById("resources_img");

if (which_nav == "courses")
	{
	a.style.display = "block";
	b.style.display = "none";
	c.src = "/_images/buttons/coursesMain_hig.png";
	d.src = "/_images/buttons/resourcesMain.png";
	}
else
	{
	a.style.display = "none";
	b.style.display = "block";
	c.src = "/_images/buttons/coursesMain.png";
	d.src = "/_images/buttons/resourcesMain_hig.png";
	}
}


function checkInputIn(which_form, which_input, should_be)
{
var a = eval("document.forms."+which_form+"."+which_input+".value");
if (a == should_be)
	{
	eval("document.forms."+which_form+"."+which_input+".value = '';");
	}
}

function checkInputOut(which_form, which_input, should_be)
{
var a = eval("document.forms."+which_form+"."+which_input+".value");
if (a == "")
	{
	eval("document.forms."+which_form+"."+which_input+".value = '"+should_be+"';");
	}
}