var nummidi = 8
day = new Date()
seed = day.getTime()
ran = parseInt(((seed - (parseInt(seed/1000,10) * 1000))/10)/100*nummidi + 1,10)

if (ran == (1)) 
midi=("songs/highway-to-hell.mid") 
if (ran == (2))
midi=("songs/y-nos-dieron-las-diez.mid") 
if (ran == (3))
midi=("songs/a-dios-le-pido.mid") 
if (ran == (4))
midi=("songs/stairway-to-heaven.mid") 
if (ran == (5)) 
midi=("songs/sin-documentos.mid") 
if (ran == (6)) 
midi=("songs/bso-el-piano.mid") 
if (ran == (7)) 
midi=("songs/bso-matrix.mid") 
if (ran == (8)) 
midi=("songs/bso-mision-imposible.mid") 

document.write('<EMBED SRC= "' + midi + '" HIDDEN=true LOOP=true TYPE=audio/midi AUTOSTART=true>')