Background Image Error: Identifying the Incorrect Operator

When attempting to style a div element with a background image using shorthand notation, some users encounter an error regarding an incorrect operator:

Error: CSS: background: / is an incorrect operator.

To rectify this issue, it's crucial to understand the correct syntax for the background property. According to CSS specifications, the / character serves as a separator between the background-position and background-size properties.

The following CSS snippet demonstrates the correct usage:

div {
  height: 100%;
  background: url('...') 100% 0/4% no-repeat;
}

In this example, "url(...) 100% 0" represents the background's position, while "4%" indicates its size. It's important to note that while background-size is optional, it should be specified alongside background-position when using shorthand notation.

Omitting the / separator or misplacing it between properties can lead to the incorrect operator error. Additionally, it's essential to specify the size without position. For instance, the following CSS code is valid:

div {
  height: 100%;
  background: url(...) 100% 0 no-repeat;
}