How to get a extension of a file using jquery or javascript? [duplicate]

Answer 1

If you need to validate multiple extensions:

var filename = "picture.jpg";
var valid_extensions = /(\.jpg|\.jpeg|\.gif)$/i;   
if(valid_extensions.test(filename))
{ 
   alert('OK');
}
else
{
   alert('Invalid File');
}

This eliminates the need to parse the string if you want to check the extension, for example, before uploading a file.

Answer 2

Use lastIndexOf() and substr():

function getFileExtension(name)
{
    int found = name.lastIndexOf('.') + 1;
    return (found > 0 ? name.substr(found) : "");
}

Note that this implementation returns an empty string if the filename doesn't contain any period character (i.e. has no extension). Implementations based on split() sometimes return the full filename in that case.

Answer 3

var text = 'example.txt',
    ext  = text.split('.')[1];

Answer 4

    if((document.form1.upload.value.lastIndexOf(".jpg")==-1) {
   alert("Please upload only .jpg extention file");
   return false;
}

lastIndexOf will return the index of the last occurrence of the specified search argument. If not found, -1 will return

Answer 5

Split the entire file name with . as the delimitter.The split will store the splitted items in an array.Take the last element of the array.

Answer 6

A simple solution is .split() and .pop() to get the last string in the array, like this:

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

This will get you just "txt" without the ., just append if needed. This also works on say: My.File.name.has.an extension.txt as well. If it doesn't have an extension it'll return the file name, so you may want to check for this...or go a completely different direction and validate against a set or known extensions via regex.