Keyboard deletes and jumps to wrong places of text

Hi guys,

I don't even know how to really explain thisproblem buthere goes:

My keyboard deletes the text I'm writingatthe wrong place when I press the delete button. For example, if I am just trying to erase the last letter of the last word I was on, andipress the delete button, it'll jump to say,the first word of the paragraph and delete the first letter. And if I press command +z, it'll sometimes erase the entire paragraph I was working on.

I checked my keyboard under system preferences and it looks okay, and I'm not on macbook so theres no trackpad that can mess up my typing. And it's not a wireless keyboard either. It's the standard applekeyboard that came with the computer.

But here's the craziest part, I think it only acts that way when I'm on Facebook. WTH???

I'm running elcapitan,

vs.10.11.4

Please help!!!