Submit формы на ExtJS

Ext.get() returns an Ext.Element, not the underlying DOM element.

The underlying element is in a property called .dom.

Try:

Ext.get('login-openid-form').dom.submit();

EDIT

If you want to get more Ext-y, you can start to leverage Ext.form.BasicForm:

var form = new Ext.form.BasicForm('login-openid-form', { standardSubmit : true });
form.submit();

That will expose a more robust form API, which is beyond the scope of this answer, but the docs (linked above) are pretty good.