function medeltal(tal1, tal2, tal3, tal4)
{
	var svar = tal1 + tal2 + tal3 + tal4 / 4;
	return(svar);
}

                tal1 = parseInt(prompt("Ange tal: "));
		tal2 = parseInt(prompt("Ange tal: "));
		tal3 = parseInt(prompt("Ange tal: "));
		tal4 = parseInt(prompt("Ange tal: "));	

		medeltal(tal1, tal2, tal3, tal4);

		document.write(svar);