Javascript字节转换

//文件大小转换
function bytesToSize(bytes) {
    if (bytes === 0) return ‘0 B‘;

    var k = 1024;

    sizes = [‘B‘, ‘KB‘, ‘MB‘, ‘GB‘, ‘TB‘, ‘PB‘, ‘EB‘, ‘ZB‘, ‘YB‘];

    i = Math.floor(Math.log(bytes) / Math.log(k));

    return (bytes / Math.pow(k, i)).toPrecision(4) + ‘ ‘ + sizes[i];
    //toPrecision(3) 后面保留一位小数，如1.0GB
　　//return (bytes / Math.pow(k, i)).toPrecision(3) + ‘ ‘ + sizes[i];  
}