restrict file upload selection to specific types

Question

Anyway to restrict the selection of file types via the element?

For instance, if I wanted only images types to be uploaded

Answer 1

There is an html attribute for this specific purpose called accept but it has little support across browsers. Because of this server side validation is recommended instead.

<input type="file" name="pic" id="pic" accept="image/gif, image/jpeg" />

If you don't have access to the backend have a look at a flash based solution like SWFUpload.

See more on this here: File input 'accept' attribute - is it useful?

Answer 2

It's better to let user select any file, and then check its type - this is better supported by the browsers:

var
    file = (el[0].files ? el[0].files[0] : el[0].value || undefined),
    supportedFormats = ['image/jpg','image/gif','image/png'];

if (file && file.type) {
    if (0 > supportedFormats.indexOf(file.type)) {
        alert('unsupported format');
    }
    else {
        upload();
    }
}

You can also check for file size using file.size property.