js格式化显示文件大小（bytes 转 KB、、、）

 1 //格式化文件大小 2 function renderSize(value){ 3 ????if(null==value||value==‘‘){ 4 ????????return "0 Bytes"; 5 ????} 6 ????var unitArr = new Array("Bytes","KB","MB","GB","TB","PB","EB","ZB","YB"); 7 ????var index=0; 8 ????var srcsize = parseFloat(value); 9 ????index=Math.floor(Math.log(srcsize)/Math.log(1024));10 ????var size =srcsize/Math.pow(1024,index);11 ????size=size.toFixed(2);//保留的小数位数12 ????return size+unitArr[index];13 }