Why doesn't background-image work?

Question

css

There is the following background code
: url("img/btn.png");
but it does not work, I tried different ways, it still does not plow, what should I do?
This has never happened before

Answer 1

To css url(../img/btn.png)
To htmlurl(img/btn.png)

Answer 2

Maybe the element's height is 0? Or the path to the image is not correct. https://jsfiddle.net/85q5vq4k/2/

Answer 3

F12 in any browser - Select the desired element and see the error. 99% that the wrong path to the picture.

Answer 4

Do you have the img folder in the css folder?

Answer 5

perhaps the path from the root needs to be specifiedbackground: url("/img/btn.png");