function centerWindow(h,w,url,alvo,params){
		wnd_T = ((screen.height/2) - (h / 2));
		wnd_L = ((screen.width/2) - (w / 2));
		window.open(url,alvo,'left='+wnd_L+',top='+wnd_T+',height='+h+',width='+w+','+params);
	}
function gEl(o){
		return document.getElementById(o);  
	}