/*使用棧stack類的實現*/function stack() {  this.dataStore = [];//保存棧內元素，初始化為一個空數組  this.top = 0;//棧頂位置，初始化為0  this.push = push;//入棧  this.pop = pop;//出棧  this.peek = peek;//查看棧頂元素  this.clear = clear;//清空棧  this.length = length;//棧內存放元素的個數}function push(element){  this.dataStore[this.top++] = element;}function pop(){  return this.dataStore[--this.top];}function peek(){  return this.dataStore[this.top-1];}function clear(){  this.top = 0;}function length(){  return this.top;}/*使用棧判斷給定字符串是否是回文的算法*/function isPalindrome(word){  var s = new stack();  for(var i = 0;i < word.length;i++){    s.push(word[i]);  }  var rword = "";  while(s.length() > 0){    rword += s.pop();  }  if(word == rword){    return true;  }else{    return false;  }}var word1 = "racecar";if(isPalindrome(word1)){  console.log(word1 + " is a palindrome")//racecar is a palindrome}