Prevent rounding errors when displaying bitcoin values in javascript
Good idea on storing it in Satoshis. With anything involving money, you want to avoid floats due to rounding errors. The best way of doing this would be to parse the value in Satoshis as a string, then simply put a decimal place 8 digits from the end to get the value in Satoshis. 

function convertToBTC(satoshis){
    var satoshi_string = satoshis.toString();
    var len_satoshi   = satoshi_string.length;
    if (len_satoshi &lt; 9){
        concat_string = concat_zeroes(9 - len_satoshi, satoshi_string);
     }
    var btc_len = concat_string.length;
    var decimal_place = btc_len-8;
    var bitcoin_string = concat_string.slice(0,decimal_place).concat('.').concat(concat_string.slice(decimal_place, btc_len));
    return bitcoin_string;
}

function concat_zeroes(num_zeroes, string1){
    while(num_zeroes){
         string1 = '0'.concat(string1);
         num_zeroes -= 1;
    }
    return string1;
}