css3选择器能否区分有输入与无输入的input？

Question

例如用伪类:focus可以区分获取焦点与无焦点的元素，并且是动态的
我想在页面input没有输入东西时一种表现，当用户一输入时又一种表现，动态的，能用选择器区分开来吗？

Answer 1

There seems to be no input, but the placeholder can be partially customized, such as setting a background color, etc. This also achieves the purpose of distinguishing whether there is content using pure CSS.

::-webkit-input-placeholder {
    color: #000;
    background: red;
    border: 1px solid #000;
}

However, you can also consider using <p contenteditable></p> and p:empty to implement the text box and its status with or without input.

<style>
    p:empty {
        color: #999;
    }
    p:empty::before {
        content: "Empty";
    }
</style>

<p contenteditable></p>

Answer 2

No, it is more appropriate to use JS to achieve this effect.

Answer 3

It doesn’t seem to exist at the moment, but if it does, it will definitely be more convenient than JS