//JS中switch case，多个case对应同一操作的写法
switch (fileformat) {
case "txt":
return "icon-wenbenwendang-txt";
break;
case "png": case "jpg": case "jpeg": case "gif":
return "icon-jpg";
break;
case "doc": case "docx":
return "icon-word";
break;
case "ppt": case "pptx":
return "icon-ppt";
break;
case "xls": case "xlsx":
return "icon-xlxs";
break;
case "apk":
return "icon-apk1";
break;
case "psd":
return "icon-psd";
break;
case "mp4" : case "avi": case "wmv":
return "icon-mov";
break;
default:
return "icon-other";
break;
}
