Unless you put one there, there will be no border on a print or on the web.
You might mean the thin border that appears in the Photoshop workspace, but that’s just the screen rendering.
But I didn’t put a black border there and originally I thought it was the screen. However, when I post it online, where my background is white, there is that black border again.
I tried triming the pixels and extending, but with no success. Help! Thank you
How was the image created?
What did you do to it in Photoshop?
Open the Info palette and see if the value goes to black when the cursor passes over the border.
Does the black border print? If not, it may be something in the html page you are inserting it in.