attr()The attr() CSS function, in the context of any property, returns the value of an attribute of an HTML element, with the option to return it as a specific type or unit. You can set a default value for missing or invalid attributes.cssCSSlimitedhttps://drafts.csswg.org/css-values-5/#attr-notationcss3-attrhttps://developer.mozilla.org/docs/Web/CSS/Reference/Values/attrcss.types.attr.declaration-valuecss.types.attr.fallbackcss.types.attr.type_functioncss.types.attr.type_function.anglecss.types.attr.type_function.colorcss.types.attr.type_function.custom-identcss.types.attr.type_function.identcss.types.attr.type_function.imagecss.types.attr.type_function.integercss.types.attr.type_function.lengthcss.types.attr.type_function.length-percentagecss.types.attr.type_function.numbercss.types.attr.type_function.percentagecss.types.attr.type_function.resolutioncss.types.attr.type_function.stringcss.types.attr.type_function.timecss.types.attr.type_function.transform-functioncss.types.attr.type_function.urlhttps://nowyoucanuse.com/features--attr.html