Can I attach a cover letter even when it is not asked for?

Question

I am submitting a resume online but it does not ask for a cover letter or have a seperate box for one, can I attach my cover letter along with my resume in the same box?

Answer 1

By all means, include it.  It will take you one step ahead of those who did not.  This is your chance to stress your great work potential and let them know why YOU are the one for the job.  It shows that you go above and beyond.  

Yes, it depends on how you scan or save your resume.  If there is only one box, save the cover letter first, then the resume to follow.

Answer 2

A cover letter is necessary; it's your way of introducing yourself and state the reasons you wish to be considered by that company.