/***************************************************************************************
 * ouvrir une fenetre pop_up
 ***************************************************************************************/

function ouvre_fenetre(w, width, height) {
	tx=(((screen.availWidth)/2)-220);
	ty=(((screen.availHeight)/2)-300);
	window = open(w,"image","toolbar=no,location=no,directories=no,menubar=no,scrollbars=yes,resizable=no,copyhistory=no,width="+width+",height="+height+",top="+ty+",left="+tx+",alwaysraised=yes");
	
}