function addPlane()
{
    var num = getNumOfPlanes();
    if (num < 10)
        num++;
    setNumOfPlanes(num);
    showPlanes(num);
    location.href = "#asub" + num;
    
}

function removePlane()
{
    var num = getNumOfPlanes();
    if (num > 1)
        num--;
    setNumOfPlanes(num);
    showPlanes(num);
    location.href = "#asub" + num;
}

function showPlanes(num)
{
    for (var i = 1; i < 11; i++)
    {
       if (i <= num)
            document.getElementById("_ctl0_ContentPlaceHolder_plane" + i).style.display = "";
        else
            document.getElementById("_ctl0_ContentPlaceHolder_plane" + i).style.display = "none";
    }
}

function getNumOfPlanes()
{
     return parseInt(document.getElementById("_ctl0_ContentPlaceHolder_AuthoringModeContainer3_NumOfPlanes").value);
}

function setNumOfPlanes(num)
{	
	
	document.getElementById("_ctl0_ContentPlaceHolder_AuthoringModeContainer3_showNumPlanes").innerText = num;
    document.getElementById("_ctl0_ContentPlaceHolder_AuthoringModeContainer3_NumOfPlanes").value = num;
}