用js怎么过滤相同值？
如题：有一个下拉框selectFlag，用js获得下拉框var selectFlag = document.getElementById('selectFlag');
然后遍历该下拉框：for(var i=0;i<selectFlag.length;i++){
var current = selectFlag.options[i];
if(current.value=="all"){
for(var j=0;j<allmember.length;j++){
var allList = allmember.options[j];
if(!radioval.checked){
if(allList.value==null || allList.value==""){
idStr += "";
}else{
idStr += allList.value;
}
}else{
idStr += allList.value + ",";
}
count += 1;
}
break;
}else{
if(!radioval.checked){
idStr += current.value;
}else{
idStr += current.value + ",";
}
count += 1;
}
}
把下拉框所有选项的值放到idStr中，怎么把下拉框中相同的选项值过滤掉呢？

[解决办法]