判断两个数组

[color=red]var selectArray = document.getElementsByName("objectprojectinfo");
var selectArray2 = document.getElementsByName("objectprojectinfo");
for(var i=0; i<selectArray.length; i+=3){
//当前比较的对象
var curselect =selectArray[i].value;
for(var j=i+3;j<selectArray2.length;j+=3){
//如果该值已选择
if(curselect==selectArray2[j].value){ parentIndex.showMessageBox('已有'+selectArray2[j].options[selectArray2[j].selectedIndex].text+'变更事项！请另选择！', 3);
selectArray2[j].focus();
return false;
}
}
}[/color]