A simple efficient and faster way of checking palindrome

palindrome.js

function palindrome(str) {
  str = str.toLowerCase(); //convert to lowercase
  let count = Math.ceil(str.length / 2), //limit for itration
      flag = true; //palindrome or not

  for(var i = 0; i < count; i++){
      //checking 0 and the last index are same or not 
      //if not same break
      if(!(str[i] === str[str.length - i - 1])){
          flag = false;
          break;
      }
  }

  return flag;
}

palindrome("something"); //false
palindrome("madam") //true

A jsben performance image