jQuery Ajax表单验证不起作用，不确定原因

Ok, so I have some jQuery code, HTML, and PHP I will post to give you guys a picture of what I am working with. As far as I can see, everything looks right but it isn't working. Even my .preventDefault() isn't preventing the form from submitting. I think it has to do with the fact that I am using a bootstrap model to hold he form, but idk why it would cause the issue. I don't have much experience with working with bootstrap though. --Edit I have the form prevented from submitting, and only need help with the ajax part. This is the first using ajax, from everything I have been researching I have it right, but i'm always getting error messages back from ajax. The error: function() is fired everytime, and I don't know how to find out why. There has to be some syntax wrong somewhere I have looked in the console and the username and password variables are assigned right at run-time.Ok, so I have some jQuery code, HTML, and PHP I