Remove a letter to make a palindrome

make-palindrome.js

function tryToGetPalinDrome(str) {
    // Returns -2 if the given word is already a palindrome
    // Returns -1 if it is impossible to make a palindrome by removing one letter from the given word
    // Returns a positive integer that shows the position of the character to remove from the word to make a palindrome
    if(str === reverse(str)) return -2; // already a palindrome
    var strlen = str.length;
    for(var i=0; i<strlen; i++) {
        var partial = str.substring(0, i) + str.substring(i+1, strlen);
        var reversed = reverse(partial);
        if(partial === reversed) {
            return i;
        }
    }
    return -1;
}

function reverse(str) {
    var newStr = '';
    for(var i=str.length; i>=0; i--) {
        newStr += str.charAt(i);
    }
    return newStr;
}