frame problem_html/css_WEB-ITnose

I wrote a frame page like this. I want to implement in this page the URLs in the two frames to jump to the corresponding pages for display, but now There is a problem that the lower frame bar covers the upper one, and the lower one is displayed. I don’t know what the problem is. Please give me some advice

Reply to the discussion (solution)

Set the height and width.

Set the height and width.
It’s not a matter of setting the height. I have already set the height, and looking at the code in the background, it jumps twice, but both times it jumps according to the url below. .