js获取上传文件大小,js实现文件上传

hml El-upload class=' base ' ref=' upload ' action=' ' accept='.CSV ' : before-upload=' before file upload ' : tonclass=' base ' size=' small ' type=' primary '上传el-upload方法handlefileuploaderchange(file ) ) lettestmsg==='CSV'(this.$message.error ) this.$t ) (certifivateno.formaterror ) ) return ) letreader=newfilereader