The read-only media property of the CSSImportRule interface returns a MediaList object, containing the value of the media attribute of the associated stylesheet.

Returns a MediaList object.

The value of media can be set by passing a string containing the media attribute; for example "print".

The following stylesheet includes a single @import rule. Therefore the first item in the list of CSS rules will be a CSSImportRule. The media property returns a MediaList object. This includes the mediaText property with a value of screen.

@import url("style.css") screen;

let myRules = document.styleSheets[0].cssRules;
console.log(myRules[0].media); //returns a MediaList

To change the media attribute of the associated stylesheet, set the value of media to a string containing the new value.

let myRules = document.styleSheets[0].cssRules;
myRules[0].media = "print";