這個是原本的語法...
<script>
<!--
var sound1="midi/1.mid"
var sound2="midi/2.mid"
var sound3="midi/3.mid"

var x=Math.random()*10
if (x<=3) x=sound1
else if (x<=6) x=sound2
else
x=sound3
if (navigator.appName=="Microsoft Internet Explorer")
document.write('<bgsound src='+'"'+x+'"'+' loop="infinite">')
else
document.write('<embed src='+'"'+x+'"'+'hidden="true" border="0" width="20" height="20" autostart="true" loop="true">')
//-->
</script>



只能播3首隨機的音樂..

如果我要增加到6首...要怎樣改.

var sound1="midi/1.mid"
var sound2="midi/2.mid"
var sound3="midi/3.mid"
var sound4="midi/4.mid"
var sound5="midi/5.mid"
var sound6="midi/6.mid"

var x=Math.random()*5 ; //0~5
x=x+1; //1~6

switch (x){
case: "1" x=sound1;break;
case: "2" x=sound2;break;
case: "3" x=sound3;break;
case: "4" x=sound4;break;
case: "5" x=sound5;break;
case: "6" x=sound6;break;
default: x=sound1;break;
}

就這樣吧
不確定能不能跑
先試試看吧
不行跑在討論