There might be cases, where You want to select element that does not have particular attribute. Not have attribute might actually mean two different aspects. One could consider empty attribute like if it not exists, while other would said that the element have attribute but empty. We will focus here on case where we treat both empty or non existent attribute as non existent.  The use case here is to select all bare links, in other words those links that do not have any CSS class applied. To select those elements, we need to use attribute selector twice, once assuming empty content and the other one assuming no attribute at all. To select elements without attribute we can use not selector extension while for empty attribute  attribute just CSS attribute selector with empty value. Example Selecting all a elements that do not have CSS class applied: a:not([class]), a[class=""]{ color: blue; } The first selector selects all a elements that do not have class attribute, the latter one selects all with empty class attribute. The same technique can be used to select any other elements with empty attribute. The selector will match for example: But will not match: Selecting Elements That Don't Have Particular Attribute or Have It Empty As in class example we need to combine not attribute selector with empty attribute selector: div:not([id]), div[id=""]{ background-color: red; } This will match any div element without (or empty)   id attribute: But will not match if element have any value on id attribute: Selecting Elements That Don't Have Particular Attribute The slightly different case is when selecting element that do not have attribute. The empty value means that attribute is empty but it still exists. To select such elements we will use only not operator. For example let's use data-name custom attribute selector: The selector would contain only not operator, let's use it on form elements: form:not([data-name]){ color: blue; } This will match elements that do not have data-name attribute: But it will not match those which have empty data-name attribute: