js实现26进制和10进制之间的转换

//将26进制转10进制
var ConvertNum = function (str) {
var n = 0;
var s = str.match(/./g);//求出字符数组
var j = 0;
for (var i = str.length - 1, j = 1; i >= 0; i--, j *= 26) {
var c = s[i].toUpperCase();
if (c < 'A' || c > 'Z') {
return 0;
}
n += (c.charCodeAt(0) - 64) * j;
}
return n;
}
//测试
var teststr = "AB";
alert(ConvertNum(teststr));
//将10进制转26进制
var Convert26=function(num){
var str="";
while (num > 0){
var m = num % 26;
if (m == 0){
m = 26;
}
str = String.fromCharCode(m + 64) + str;
num = (num - m) / 26;
}
return str;
}

//测试
var num = 28;
alert(Convert26(num));