window.onload = function(){
var agregar = document.getElementById("agregar");
	agregar.onclick = function(){
		var wid = 400;
		var awid = ((screen.availWidth)-wid)/2;
		var hei = 300;
		var heig = ((screen.availHeight)-hei)/2;
		window.open("http://www.videos-divertidos.com.ar/agregarweb.htm","AgregarWeb","width="+wid+",left="+awid+",height="+hei+",top="+heig+"");	
	}
}