javaScript格式化文件大小

///格式化文件大小
function formatFileSize(fileSize) {
    if (fileSize < 1024) {
        return fileSize + 'B';
    } else if (fileSize < (1024*1024)) {
        var temp = fileSize / 1024;
        temp = temp.toFixed(2);
        return temp + 'KB';
    } else if (fileSize < (1024*1024*1024)) {
        var temp = fileSize / (1024*1024);
        temp = temp.toFixed(2);
        return temp + 'MB';
    } else {
        var temp = fileSize / (1024*1024*1024);
        temp = temp.toFixed(2);
        return temp + 'GB';
    }
}