function selectDiv(nr)  {
		var elemDiv1 = document.getElementById("inv_type_1");
		var elemDiv2 = document.getElementById("inv_type_2");
		var elemDiv3 = document.getElementById("inv_type_3");
		
		var elemImg1 = document.getElementById("img1");
		var elemImg2 = document.getElementById("img2");
		var elemImg3 = document.getElementById("img3");

if(nr == 1) {
		elemDiv1.style.display = "block";
		elemDiv2.style.display = "none";
		elemDiv3.style.display = "none"; 
		elemImg1.src = "images/minus_button.gif";
		elemImg2.src = "images/plus_button.gif";
		elemImg3.src = "images/plus_button.gif";    
                               
//elemDiv1.style.backgroundColor = "#5ff";           
//elemDiv1.innerHTML = "<p>new text</p>";        
} else if (nr == 2) {
		elemDiv1.style.display = "none";
		elemDiv2.style.display = "block";
		elemDiv3.style.display = "none";
		
		elemImg1.src = "images/plus_button.gif";
		elemImg2.src = "images/minus_button.gif";
		elemImg3.src = "images/plus_button.gif";                                                                

} else if (nr == 3)            {
		elemDiv1.style.display = "none";
		elemDiv2.style.display = "none";
		elemDiv3.style.display = "block"; 
		
		elemImg1.src = "images/plus_button.gif";
		elemImg2.src = "images/plus_button.gif";
		elemImg3.src = "images/minus_button.gif";                                                        

} else {
		alert("invalid div id");
		return false;
}
}