Add ID to Button in Javascript

Question

I'm currently trying to find a way to add an ID to an html button using a javascript injection. The html is simple and looks like this:

<button type="submit" class="submit btn primary-btn" tabindex="4">Sign in</button>

Now, as you can see, it doesn't have an ID or a name, making it a bit difficult to find using spynner in Python. What javascript could I inject to add an ID to this script? Would having javascript search for that entire string and then replace the entire string with an ID added ot it? Or is there a better way of going about it?

Answer 1

To ensure html integrity I would suggest:

$('.submit.btn.primary-btn').eq(0).attr('id', 'foobar');