Excel Sheet Column Number.js

/*Related to question Excel Sheet Column Title

Given a column title as appear in an Excel sheet, return its corresponding column number.

For example:

    A -> 1
    B -> 2
    C -> 3
    ...
    Z -> 26
    AA -> 27
    AB -> 28*/

/**
 * @param {string} s
 * @return {number}
 */
var titleToNumber = function(s) {
    if(s=="")
        return 0
    else
        return (s[0].charCodeAt(0)-64) * Math.pow(26,s.length-1) + titleToNumber(s.slice(1))
};