var FCTIMER = 15;
var FCBUSY = false;
 
function fcExpand(id, speed) {
if(!FCBUSY) {
var el = document.getElementById(id);
el.style.overflow = 'hidden';
var temph = el.offsetHeight;
el.style.height = 'auto';
if(temph !== el.offsetHeight) {
el.orgh = el.offsetHeight;
el.style.height = temph;
}
FCBUSY = true;
el.timer = setInterval(function(){fcSlide(el, 1, speed)}, FCTIMER);
}
}
 
function fcCollapse(id, speed) {
if(!FCBUSY) {
var el = document.getElementById(id);
el.style.overflow = 'hidden';
var temph = el.offsetHeight;
el.style.height = 'auto';
if(temph !== el.offsetHeight) {
el.orgh = el.offsetHeight;
el.style.height = temph;
}
FCBUSY = true;
el.timer = setInterval(function(){fcSlide(el, 0, speed)}, FCTIMER);
}
}
 
function fcToggle(id, speed) {
if(document.getElementById(id).offsetHeight > 0) {
fcCollapse(id, speed);
} else {
fcExpand(id, speed);
}
}
 
function fcSlide(el, direction, speed) {
var curh = el.offsetHeight;
if(direction == 0) { speed = 0 - speed; }
 
if(direction == 0 && (curh + speed) < 1) {
el.style.height = '0px';
clearInterval(el.timer);
FCBUSY = false;
} else if(direction == 1 && (curh + speed) > (el.orgh - 1)) {
el.style.height = el.orgh + 'px';
clearInterval(el.timer);
FCBUSY = false;
} else {
el.style.height = curh + speed + 'px';
}
}