How to extract extension from filename string in Javascript? [duplicate]

Answer 1

I would recommend using lastIndexOf() as opposed to indexOf()

var myString = "this.is.my.file.txt"
alert(myString.substring(myString.lastIndexOf(".")+1))

Answer 2

Use the lastIndexOf method to find the last period in the string, and get the part of the string after that:

var ext = fileName.substr(fileName.lastIndexOf('.') + 1);

Answer 3

Better to use the following; Works always!

var ext =  fileName.split('.').pop();

This will return the extension without a dot prefix. You can add "." + ext to check against the extensions you wish to support!

Answer 4

I personally prefer to split the string by . and just return the last array element :)

var fileExt = filename.split('.').pop();

If there is no . in filename you get the entire string back.

Examples:

'some_value'                                   => 'some_value'
'.htaccess'                                    => 'htaccess'
'../images/something.cool.jpg'                 => 'jpg'
'http://www.w3schools.com/jsref/jsref_pop.asp' => 'asp'
'http://stackoverflow.com/questions/680929'    => 'com/questions/680929'

Answer 5

get the value in the variable & then separate its extension just like this.

var find_file_ext=document.getElementById('filename').value;
var file_ext=/[^.]+$/.exec(find_file_ext); 

This will help you.

Answer 6

Try this. May solve your problem.

var file_name_string = "file.name.string.png"

var file_name_array = file_name_string.split(".");
var file_extension = file_name_array[file_name_array.length - 1];

Regards