///////////////////////////////////////
//              POP-UP               //
///////////////////////////////////////
var MyWin = '';
function pop_up(url,nom,lar,hau,opt)	{
	//default value
	url = typeof(url) != 'undefined' ? url 	: window.location;
	nom = typeof(nom) != 'undefined' ? nom 	: 'pop_up';
	lar = typeof(lar) != 'undefined' ? lar 	: 300;
	hau = typeof(hau) != 'undefined' ? hau 	: 400;
	opt = typeof(opt) != 'undefined' ? opt 	: 'menubar=no,scrollbars=no,statusbar=no';
	//popup does not exist
	if (MyWin == '' || MyWin.closed) {
		MyWin = window.open(url,nom,opt);
	} else {
	//else change location
		MyWin.location.href = url;
	}
	//size
	MyWin.resizeTo(lar,hau);
	//pop up position
	var top = (screen.height-hau)/2;
	var left = (screen.width-lar)/2;
	MyWin.moveTo(left,top);
	//show on top
	MyWin.focus();
}