function popAfbeeldingAlsAchtergrond(uri,width,height){
	var properties,vensternaam;
	properties = "toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=0,width="+width+",height="+height+",left=100,top=20,marginwidth=0,leftmargin=0,marginheight=0,topmargin=0";
	vensternaam = randomString();
	nieuwVenster=window.open(uri,vensternaam,properties);
	nieuwVenster.document.write('<html><head><\/head><body background="'+uri+'"><table width="100%" height="100%"><tr><td><a href="javascript:close();"><img border="0" src="/img/transparantepix.gif" width="100%" height="100%" alt="sluit dit scherm" title="sluit dit scherm"></a></td></tr></table><\/body><\/html>')
	// is onderstaande nog nodig ??
	//nieuwVenster.resizeBy(width-nieuwVenster.document.body.clientWidth,height-nieuwVenster.document.body.clientHeight)
	nieuwVenster.focus()
}

function randomString() {
	var chars = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXTZabcdefghiklmnopqrstuvwxyz";
	var string_length = 8;
	var randomstring = '';
	for (var i=0; i<string_length; i++) {
		var rnum = Math.floor(Math.random() * chars.length);
		randomstring += chars.substring(rnum,rnum+1);
	}
	return randomstring;
}
