function nb_aleatoire(nb) { nombre= Math.floor(Math.random() * nb)+1; } nb_aleatoire(1) if (screen.width<=640) image='http://www.reikirama.net/images/fonds/640x480_'+nombre+'.jpg'; else if (screen.width<=800) image='http://www.reikirama.net/images/fonds/800x600_'+nombre+'.jpg'; else if (screen.width<=1024) image='http://www.reikirama.net/images/fonds/1024x768_'+nombre+'.jpg'; else if (screen.width<=1152) image='http://www.reikirama.net/images/fonds/1152x864_'+nombre+'.jpg'; else if (screen.width<=1280) image='http://www.reikirama.net/images/fonds/1280x1024_'+nombre+'.jpg'; else image='http://www.reikirama.net/images/fonds/1600x1200_'+nombre+'.jpg'; document.write(''); //alert(image);