问题很简单

推荐Eclipse.
我当初从JCreater开始学，那是J2SE；
学J2EE时用的是JDeveloper 10g.

<script>
var a1=Array();
var a2=Array();
a1[0]="javascript";
a1[1]='css';
a1[2]='php';
a2[0]=Array(0,"javscript简介",0);
a2[1]=Array(1,"javscript对象",0);
a2[2]=Array(2,"javscript语法",0);
a2[3]=Array(3,"javscript应用",0);
a2[4]=Array(4,"css简介",1);
a2[5]=Array(5,"css特点",1);
a2[6]=Array(6,"css语法",1);
a2[7]=Array(7,"css应用",1);
a2[8]=Array(8,"php简介",2);
a2[9]=Array(9,"php对象",2);
a2[10]=Array(10,"php语法",2);
a2[11]=Array(11,"php应用",2);
function sel(val,obj,arr){
obj.length=0;
for(i=0;i<a2.length;i++){
if(arr[i][2]==val)obj[obj.length]=new Option(arr[i][1],arr[i][0]);
}
}
</script>
<form name="form1" method="post" acti