用javascript写的一个类似堆栈取出几个算式中的运算符号的代码

<script>
function testA(){
var stack = new Array("a","b","c","d","e","f","g","h","i","j","k","l");
var buff = new Array();

function getComb(stack, buff)
{
if(stack.length + buff.length < 5) return; //字母不够了，不用再试
while(stack.length > 0) //字母还没用完
{
buff.push(stack.shift()); //选取字母
if(buff.length < 5) //还没到5个字母
{
getComb(stack.slice(0), buff.slice(0)); //继续选取
}
else if(buff.length == 5)
{
document.write(buff+"<br>"); //够数量了，输出
}
buff.pop(); //丢弃用过的字母
}
return;
}
getComb(stack, buff);
}


function testB(strA){
  var buffer2 = new Array();
  var initCount = 0;
  var str = strA;
  var countPoint = 0;
  if(str.indexOf("+")>0||str.indexOf("-")>0||str.indexOf("*")>0||str.indexOf("/")>0){
    for(var i=0; i<str.length;i++){
      if(str.charAt(i)=='('){
        countPoint = 1;
        buffer1.push("(");
//        alert("222222222222============"+buffer1.length);
      }
      if(str.charAt(i)==')'){
        countPoint = i;
        buffer1.pop("(");
//        alert("222222222222============"+buffer1.length);
      }
      if(countPoint>0&&buffer1.length==0){
//        alert("222222222222============"+buffer1.length);
        countPoint=2;
      }
      if(countPoint==2){
        buffer2.push(str.charAt(i+1));
        countPoint = 0;
      }     
    }
//    buffer2.pop();
    alert("3333333333========="+buffer2.toString());
  }else{
  alert("sdfffdfdsafdas");
  }
}
function testA(){
  var ste = document.all("aa").value;
  alert(ste);
  testB(ste);
}

var buffer1 = new Array();
var ra = 0;
var rb = 0;
var page = 0;
var tmpLength = 0;
var counterNum = 0;
var strddd = "";
function aa(){
  testA();
  if(counterNum==0){
    tmpLength = tmpLength;
    ra = dafd;
    rb = dfd;
    page = dfds;
    strddd = daadfadf+buffer1[counterNum]; 
    counterNum++;
   
   
   
  }
  if(ra == ca&& rb==cb&&page==pb){
    strddd = daadfadf+buffer1[counterNum];
    counterNum++;
  }
 

 
}
</script>
<input type="text" name="aa" value="" />
<input type="button" name="dsd" value="测试堆栈" onclick="testA()">