function jumpobj(elem, range, startfunc, endfunc) {
	var curmax = range = range || 6;
   	startfunc = startfunc || function(){};
	endfunc = endfunc || function(){};
	var drct = 0;
	var step = 1;

	init();

	function init() { elem.style.position = 'relative';active() }
	function active() { elem.onmouseover = function(e) {if(!drct)jump()} }
	function deactive() { elem.onmouseover = null }

	function jump() {
		 var t = parseint(elem.style.top);
		if (!drct) motionstart();
		else {
			var nexttop = t - step * drct;
			if (nexttop >= -curmax && nexttop <= 0) elem.style.top = nexttop + 'px';
			else if(nexttop < -curmax) drct = -1;
		   else {
				var nextmax = curmax / 2;
				if (nextmax < 1) {motionover();return;}
				curmax = nextmax;
				drct = 1;
			}
		}
		settimeout(function(){jump()}, 200 / (curmax+3) + drct * 3);
	 }
	function motionstart() {
		startfunc.apply(this);
		elem.style.top='0';
		drct = 1;
	}
	  function motionover() {
		endfunc.apply(this);
		curmax = range;
		drct = 0;
		elem.style.top = '0';
	}

	this.jump = jump;
	this.active = active;
	this.deactive = deactive;
}