function expand_collapse(number)
{
 div = document.getElementById("div_" + number);
 img = document.getElementById("img_" + number);
 if (div.style.display == 'none')
 {
   div.style.display = 'block';
   img.src = "/lib/img/minus.gif";
 }
 else if (div.style.display == 'block')
 {
   div.style.display = 'none';
   img.src = "/lib/img/plus.gif";
 }
}

function collapse(number)
{
 div = document.getElementById("div_" + number);
 img = document.getElementById("img_" + number);
 if (!(div && img)) return false;
 div.style.display = 'none';
 img.src = "/lib/img/plus.gif";
}

function expand(number)
{
 div = document.getElementById("div_" + number);
 img = document.getElementById("img_" + number);
 if (!(div && img)) return false;
 div.style.display = 'block';
 img.src = "/lib/img/minus.gif";
}

function collapse_all()
{
 collapse(0);
 collapse(1);
 collapse(2);
 collapse(3);
 collapse(4);
 collapse(5);
 collapse(6);
 collapse(7);
 collapse(8);
 collapse(9);
 collapse(10);
 collapse(11);
 collapse(12);
 collapse(13);
 collapse(14);
 collapse(15);
 collapse(16);
 collapse(17);
 collapse(18);
 collapse(19);
 collapse(20);
 collapse(21);
 collapse(22);
 collapse(23);
 collapse(24);
 collapse(25);
 collapse(26);
}

function expand_all()
{
 expand(0);
 expand(1);
 expand(2);
 expand(3);
 expand(4);
 expand(5);
 expand(6);
 expand(7);
 expand(8);
 expand(9);
 expand(10);
 expand(11);
 expand(12);
 expand(13);
 expand(14);
 expand(15);
 expand(16);
 expand(17);
 expand(18);
 expand(19);
 expand(20);
 expand(21);
 expand(22);
 expand(23);
 expand(24);
 expand(25);
 expand(26);
}