w3cSchool初级脚本算法答案(1-3)

1. 翻转字符串算法挑战

function reverseString(str) {
    var arr = str.split('');
    var dArr = arr.reverse();
    var newStr = dArr.join('');
    return newStr;
}

reverseString("hello");

2.阶乘算法挑战

function factorialize(num) {
    var newNum = 1;
    for(var i = 1;i<=num;i++){
        newNum *= i;
    }
    return newNum;
}

factorialize(5);

3.回文算法挑战

function palindrome(str) {
    var reg = /[^a-zA-Z0-9]/g;
    var Str = str.replace(reg,'');
    var newStr = Str.toLowerCase();
    return newStr == reverseString(newStr);
}
function reverseString(str) {
    var arr = str.split('');
    var dArr = arr.reverse();
    var newStr = dArr.join('');
    return newStr;
}
palindrome("race car");