function showhide(id, show)
{
	if(typeof show == 'undefined')
		show = document.getElementById(id).style.display != 'block' ;
	document.getElementById(id).style.display = show ? 'block' : 'none' ;
}



function classAdd(e, c)
{
	a = e.className.split(' ') ;
	a.push(c) ;
	e.className = arrayFilter(arrayUnique(a)).join(' ') ;
}

function classRemove(e, c)
{
	e.className = arrayFilter(arrayUnique(arrayUnset(c, e.className.split(' ')))).join(' ') ;
}

function imgSet(id, src, width, height) {
	var el = document.getElementById(id) ;
	el.src    = src    ;
	el.width  = width  ;
	el.height = height ;
}