// JavaScript Document
// preset UI variables
var content_height = 0;
var counter = 0;
// set toggle to default true
var toggle = true;
// set counter equal to the height of the content
var counter_constant = 10;
var ease = 50;
var fps = 24;
var time = .5;
//
function init(){
	setVariables();
}
function setVariables(){
	  var parent = document.getElementById('articles_list');
	  // find total number of list items
	  var childCount = parent.getElementsByTagName('li').length;
	  // set content_height based on line-height x list items count
	  content_height = 18 * childCount;
	  // set counter equl to content_height
	  counter = content_height;
	  // adjust for frame rate
	  time = time*16.67;
	  ease = ease/Math.round(fps*time);
	  // convert from miliseconds
	  fps = 1000/fps;
}
function open_box(){
	var content = document.getElementById('left_nav_content');
	var button_up = document.getElementById('left_nav_btn_up');
	var button_down = document.getElementById('left_nav_btn_down');
	var button_selected = document.getElementById('left_nav_btn_selected');
    content.style.display = "block";
    if (counter > content_height-counter_constant){
		var ht = content_height + "px";
        content.style.height = ht;
        counter = content_height;
		button_up.style.display = "block";
		button_down.style.display = "none";
		button_selected.style.display = "none";
    } else {
        if (counter < counter_constant){
            counter = counter_constant;
        }
        counter += Math.round(ease*counter);
        var ht = counter + "px";
        content.style.height = ht;
		button_up.style.display = "none";
		button_down.style.display = "none";
		button_selected.style.display = "block";        
        repeat_open();
    }    
}
function close_box(){
    var content = document.getElementById('left_nav_content');
	var button_up = document.getElementById('left_nav_btn_up');
	var button_down = document.getElementById('left_nav_btn_down');
	var button_selected = document.getElementById('left_nav_btn_selected');
	//<a href="javascript:box_top_click();"><img src="img/button_arrow.gif" border="0" /></a>
    if (counter < counter_constant){
        content.style.display = "none";
        counter = counter_constant;
		button_up.style.display = "none";
		button_down.style.display = "block";
		button_selected.style.display = "none";
    } else {
        counter -= Math.round(ease*counter);
        var ht = counter + "px";
        content.style.height = ht;
		button_up.style.display = "none";
		button_down.style.display = "none";
		button_selected.style.display = "block";
        repeat_close();
    }
}
function repeat_open(){
    var t = setTimeout("open_box()",fps);
}
function repeat_close(){
    var t = setTimeout("close_box()",fps);
}
function box_top_click(){
    if (toggle == true){
        close_box();
        toggle = false;
    } else{
        open_box();
        toggle = true;
    }
}