How can i get file extensions with javascript?

Question

See code:

var file1 ="50.xsl";
var file2 =30.doc";"
getFileExtension(file1); //returs xsl
getFileExtension(file2); //returs doc

function getFileExtension(filename) {
/*TODO*/
}

Answer 1

return filename.replace(/\.([a-zA-Z0-9]+)$/, "$1");

edit: Strangely (or maybe it's not) the $1 in the second argument of the replace method doesn't seem to work... Sorry.

Answer 2

var arr=file1.split(".") return arr[1]

Answer 3

return /[^.]+$/.exec(filename);

Should do it.

Edit: In response to PhiLho's comment, use something like:

return (/[.]/.exec(filename)) ? /[^.]+$/.exec(filename) : undefined;

Answer 4

var parts = filename.split('.');
return parts[parts.length-1];

Answer 5

function getFileExtension(filename)
{
  var ext = /^.+\.([^.]+)$/.exec(filename);
  return ext == null ? "" : ext[1];
}

Tested with "a.b" (=> "b"), "a" (=> ""), ".hidden" (=> ""), "" (=> ""), null (=> "")
Also "a.b.c.d" (=> "d"), ".a.b" (=> "b"), "a..b" (=> "b").

Answer 6

function file_get_ext(filename)
    {
    return typeof filename != "undefined" ? filename.substring(filename.lastIndexOf(".")+1, filename.length).toLowerCase() : false;
    }

Answer 7

I just realized that it's not enough to put a comment on p4bl0's answer, though Tom's answer clearly solves the problem:

return filename.replace(/^.*?\.([a-zA-Z0-9]+)$/, "$1");

Answer 8

function extension(fname) {

var pos = fname.lastIndexOf(".");

var strlen = fname.length;

if(pos != -1 && strlen != pos+1){

var ext = fname.split(".");

var len = ext.length;

var extension = ext[len-1].toLowerCase();

}else{

extension = "No extension found";

}

return extension;

}

//usage

extension('file.jpeg')

always returns the extension lower cas so you can check it on field change works for:

file.JpEg

file (no extension)

file. (noextension)

Answer 9

function func() { var val=document.frm.filename.value; var arr=val.split("."); alert( arr[arr.length-1] ); var arr1=val.split("\"); alert(arr1[arr1.length-2]); if(arr[1]=="gif" || arr[1]=="bmp" || arr[1]=="jpeg") { alert("this is an image file "); } else { alert("this is not an image file"); } }

Answer 10

return filename.split('.').pop();

Keep it simple :)