function elem(id) { return document.getElementById(id); }

function input_value(obj,vl,chk) {
	if (obj) {
		if (obj.value == chk) obj.value = vl;
	}
}

function input_fcs(obj,chk,cls) {
	if (obj) {
		obj.className = cls;
		if (obj.value == chk) obj.value = '';
	}
}

function input_blr(obj,chk,cls) {
	if (obj) {
		if (obj.value == '') { 
			obj.value = chk;
			obj.className = cls;
		}
	}
}

function pon(obj) {
	if (obj == undefined) return;
	var id = parseInt(obj.id);
	
	var el = elem(id+'on');
	if (el != undefined) obj.src = el.src;
}

function pof(obj) {
	if (obj == undefined) return;
	var id = parseInt(obj.id);
	var el = elem(id+'off');
	if (el != undefined) obj.src = el.src;
}