javascript - The code for changing the box image in the drop-down list. Is there anything wrong?

Question

The previous js part

body part

Sorry, I don’t know why I can’t copy the code. I can only Posted pictures

Answer 1

changed to

#tu {
    background-image: url("./images/xxxxxxxxxxxx.jpg");
}

#tu 有没有宽高？

Give it a try

Answer 2

Will tu.style.backgroundImage 改成 tu.style.background try it.