js中字节B转化成KB，MB，GB

 1 function change(limit){
 2     var size = "";
 3     if(limit < 0.1 * 1024){                            //小于0.1KB，则转化成B
 4         size = limit.toFixed(2) + "B"
 5     }else if(limit < 0.1 * 1024 * 1024){            //小于0.1MB，则转化成KB
 6         size = (limit/1024).toFixed(2) + "KB"
 7     }else if(limit < 0.1 * 1024 * 1024 * 1024){        //小于0.1GB，则转化成MB
 8         size = (limit/(1024 * 1024)).toFixed(2) + "MB"
 9     }else{                                            //其他转化成GB
10         size = (limit/(1024 * 1024 * 1024)).toFixed(2) + "GB"
11     }
12 
13     var sizeStr = size + "";                        //转成字符串
14     var index = sizeStr.indexOf(".");                    //获取小数点处的索引
15     var dou = sizeStr.substr(index + 1 ,2)            //获取小数点后两位的值
16     if(dou == "00"){                                //判断后两位是否为00，如果是则删除00                
17         return sizeStr.substring(0, index) + sizeStr.substr(index + 3, 2)
18     }
19     return size;
20 }
21 
22 var newLimit = change(1048576);
23 console.log(newLimit);