file extension - lastindexOf

JavaScript

function openFile(file) {
    var msg = ''
    var extension = file.substr( (file.lastIndexOf('.') +1) );
    switch(extension) {
        case 'jpg':
        case 'png':
        case 'gif':
            msg=('was jpg png gif');
        break;
        case 'zip':
        case 'rar':
            msg=('was zip rar');
        break;
        case 'pdf':
            msg=('was pdf');
        break;
        default:
            msg=('who knows');
    
    }
$("body").prepend(msg);
};

openFile("myfil.e.png");