产生一段随机字符串

[javascript]代码库

function(size) randomString {
    size = size || 6;
    var chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789', // 62个字符
        maxNum = chars.length,
        ret = '';
    while (size > 0) {
        ret += chars.charAt(Math.floor(Math.random() * maxNum));
        size--;
    }
    return ret;
}