function Aleatoire(mini,maxi){
	if (mini>maxi) {
		var y; y=maxi; maxi=mini; mini=y;
	}
	return mini+Math.round(Math.random() * (maxi-mini));
}

document.write('<a href="" target="_blank"><img src="http://media.cash-program.com/ban/banrandom.php?site=26&format=728x90&id=all&cle='+Aleatoire(1,10000)+'" border="0"></a>');