未设置 | unset (Cascading & Inheritance) - CSS 中文开发手册
unsetCSS关键词当它从其父继承了继承值,而其初始值没有,则unset重置属性。换句话说,它inherit在第一种情况下就像initial关键字,而在第二种情况下就像关键字一样。它可以应用于任何CSS属性,包括CSS简写all。
.foo {
  color: blue;
}
.bar {
  color: green;
}
p {
  color: red;
}
.bar p {
  color: unset;
} <p>This text is red.</p> <div class="foo"> <p>This text is also red.</p> </div> <div class="bar"> <p>This text is green (default inherited value).</p> </div>
结果:
div {
  border: 1px solid green;
}
p {
  border: 1px solid red;
}
.bar p {
  border-color: unset;
} <p>This text has a red border.</p> <div> <p>This text has a red border.</p> </div> <div class="bar"> <p>This text has has a black border (initial default, not inherited).</p> </div>
结果:
| Specification | Status | Comment | 
|---|---|---|
| CSS Cascading and Inheritance Level 4The definition of ‘unset‘ in that specification. | Working Draft | No changes from Level 3. | 
| CSS Cascading and Inheritance Level 3The definition of ‘unset‘ in that specification. | Candidate Recommendation | Initial definition. | 
| Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari | 
|---|---|---|---|---|---|
| Basic support | 41 | 27 (27) | Edge build 10565+ | 28 | 9.1 | 
| Feature | Android | Firefox Mobile (Gecko) | IE Phone | Opera Mobile | Safari Mobile | 
|---|---|---|---|---|---|
| Basic support | No support | 27.0 (27) | No support | No support | 9.3 | 
未设置 | unset (Cascading & Inheritance) - CSS 中文开发手册 - Break易站
原文:https://www.cnblogs.com/breakyizhan/p/13221798.html