function move_up(array_name)
{
	//go through in order swapping each selected one with the one above it
	var element = document.getElementById(array_name);
	for( var i = 1; i < element.options.length; ++i)
	{
		if(element.options[i].selected)//todo first element selected
		{
			element.options[i].selected=false;
			lower = element.options[i-1].value;
			
			//transfer over
			element.options[i-1] = new Option(element.options[i].value,element.options[i].value);
			element.options[i] = new Option(lower,lower);
		}
	}
}

function move_down(array_name)
{
	//go through in order swapping each selected one with the one above it
	var element = document.getElementById(array_name);
	for( var i = 0; i < element.options.length-1; ++i)
	{
		if(element.options[i].selected)//todo first element selected
		{
			element.options[i].selected=false;
			lower = element.options[i+1].value;
			
			//transfer over
			element.options[i+1] = new Option(element.options[i].value,element.options[i].value);
			element.options[i] = new Option(lower,lower);
		}
	}
}

function remove(array_name)
{
	var element = document.getElementById(array_name);
	for( var i = 0; i < element.options.length; ++i)
	{
		if(element.options[i].selected)//todo first element selected
		{
		element.options[i].selected = false;
			element.options[i] = null;
		}
		
	}
}

function insert(array_name)
{
	var element = document.getElementById(array_name);
	
	var str = prompt ("Name","");
	if((str!='') && (str!=null))
	{
		//check for uniqueness
		for( var i = 0; i < element.options.length; ++i)
		{
			if(element.options[i].value == str)
			{
				alert('Already exists');
				return;
			}	
		}
			newOption = new Option(str, str);
			element.options[element.options.length] = newOption;
	}
}

function select_all(array_of_names)
{
	for(var j = 0; j < array_of_names.length; ++j)
	{
		//go through in order swapping each selected one with the one above it
		var element = document.getElementById(array_of_names[j]);
		if(element != null)
		{
			for( var i = 0; i < element.options.length; ++i)
			{
				element.options[i].selected=true;
			}
		}
	}
}