javascript - get the filename and extension from input type=file

问题

I have a file upload input and when I click the browse button and select the file, I want the filename and extension to appear in two input text boxes (see code sample).

It works correctly with the extension, but the filename also shows the path which gives me the fakepath warning.

I understand why, but what's a good way to do this and just get the filename into that box. I don't need the path.

function getoutput(){
    outputfile.value=inputfile.value.split('.')[0];
    extension.value=inputfile.value.split('.')[1];}

    <input id='inputfile' type='file' name='inputfile' onChange='getoutput()'><br>
    Output Filename <input id='outputfile' type='text' name='outputfile'><br>
    Extension <input id='extension' type='text' name='extension'>

回答1:

Use lastIndexOf to get the last \ as an index and use substr to get the remaining string starting from the last index of \

function getFile(filePath) {
        return filePath.substr(filePath.lastIndexOf('\\') + 1).split('.')[0];
    }

    function getoutput() {
        outputfile.value = getFile(inputfile.value);
        extension.value = inputfile.value.split('.')[1];
    }

<input id='inputfile' type='file' name='inputfile' onChange='getoutput()'><br>
    Output Filename <input id='outputfile' type='text' name='outputfile'><br>
    Extension <input id='extension' type='text' name='extension'>

UPDATE

function getFileNameWithExt(event) {

  if (!event || !event.target || !event.target.files || event.target.files.length === 0) {
    return;
  }

  const name = event.target.files[0].name;
  const lastDot = name.lastIndexOf('.');

  const fileName = name.substring(0, lastDot);
  const ext = name.substring(lastDot + 1);

  outputfile.value = fileName;
  extension.value = ext;
  
}

<input id='inputfile' type='file' name='inputfile' onChange='getFileNameWithExt(event)'><br>
  Output Filename <input id='outputfile' type='text' name='outputfile'><br>
  Extension <input id='extension' type='text' name='extension'>

回答2:

This is bit old post...just for info

   var files = event.target.files
   var filename = files[0].name
   var extension = files[0].type

In the type you will find the extension for eg: if it is jpeg image then,

extension = image/jpeg

or if pdf then,

extension = application/pdf

To obtain the exact value, perform extension.replace(///g, ''). you will get the value.

回答3:

var filePath = $("#inputFile").val(); 
var file_ext = filePath.substr(filePath.lastIndexOf('.')+1,filePath.length);
console.log("File Extension ->-> "+file_ext);

It will work if you have dots in filename.

回答4:

You could try this out:

var fullPath = inputfile.value.split('.')[0];
var filename = fullPath.replace(/^.*[\\\/]/, '');
outputfile.value=filename;`

This should remove everything except the filename.

I got it from How to get the file name from a full path using JavaScript?.

回答5:

First get the filename, then slice it to various parts.

const media_file = event.target.files[0] // event is from the <input> event
const filename = media_file.name

let last_dot = filename.lastIndexOf('.')
let ext = filename.slice(last_dot + 1)
let name = filename.slice(0, last_dot)

回答6:

from file[0].type you can get the extension

file[0] looks like File { name: "hcl_icon.ico", lastModified: 1559301004000, webkitRelativePath: "", size: 1150, type: "image/x-icon" }

or by File reader reader.onload = function (e){} e.target.result gives the src of the file contains Data have extension

回答7:

Simple and quick.

   var files = event.target.files[0]
   // for getting only extension 
   var fileExtension = files.type.split("/").pop();
   var fileName = files.name

回答8:

Here is a handy code.

    String extension = fileName.substring(fileName.lastIndexOf('.')+1);
    String name = fileName.substring(0, fileName.lastIndexOf('.'));

来源：https://stackoverflow.com/questions/43708127/javascript-get-the-filename-and-extension-from-input-type-file