3

两种 CSS（一个在 light dom 中，一个在 shadown dom 中）都对标签有影响。
姓名和电话也受全局 CSS at 和 Shadow Scope CSS 的影响！！！
为什么 ？？？？？我不想要它。
我预计它们只是受到模板范围内的 Sahdow 范围 CSS 的影响。
我希望我能从你那里得到一些想法。

https://plnkr.co/edit/Asr1S1UFvhmhtZeWm5k8

//CREATE CUSTOM ELEMENT
var MyContactProtype = Object.create(HTMLElement.prototype);
MyContactProtype.createdCallback = function() {
  //retrieve template
  var tpl = document.querySelector('#contact-form-tpl');
  var tpl_ct = document.importNode(tpl.content, true);

  //this <=> my-contact element -> create shadow
  var shadowRoot = this.createShadowRoot();

  //show template in shadow DOM
  shadowRoot.appendChild(tpl_ct);
};

//REGISTER CUSTOM ELEMENT
document.registerElement("my-contact", {
  prototype: MyContactProtype
});
span {/* global CSS*/
  text-decoration: line-through
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/document-register-element/1.11.0/document-register-element.js"></script>
<span>HELLO</span>
<!--line through by css at LINE 6: OK-->
<my-contact>
  <h1 class="header-contact-form">Contact X</h1>
  <span class="name">this is my name</span>
  <span class="phone">this is my phone</span>
</my-contact>


<template id="contact-form-tpl">
  <style>
    span {/* shadow scope CSS*/
      text-decoration: underline
    }
  </style>
  <fieldset>
    <legend>
      <content select="h1.header-contact-form"></content>
      <!--
      Name and Phone are effected by CSS at line 6 and 21 too!!!
      WHY ????? I dont want it.
      I expected they are just effeted by CSS line 21 which is in template scope.
      -->
      <div>
        Name: <span><content select="span.name"></content></span>
      </div>
      <div>
        Phone: <content select="span.phone"><span></span></content>
      </div>
      <span>TEST</span><!-- only apply css at line 21: OK-->
    </legend>
  </fieldset>
</template>

4

1 回答 1

4

这是 CSS 样式的正常行为。插入到 Shadow DOM 中的元素<content>（在您的示例<span class=name>...</span>中：）实际上是普通 DOM 的一部分，因此受到全局 CSS 样式的影响。

如果你不想要它，你应该尝试另一种技术，比如将 light DOM 元素复制到 Shadow DOM 中，而不是使用<content>.

此外，您应该使用自定义元素 v1 (and customElements.define()) 和Shadow DOM v1 (and ) 而不是已弃用<slot>的自定义元素 v0 ( registerElement()) 和 Shadow DOM v0 ( )。<content>

使用 Shadow DOM v1，您可以::slotted()在 Shadow DOM 内部使用来选择和设置插入元素的样式。

<style>然后，您可以使用!important修饰符重载 Shadow DOM 中的 CSS 规则：

第 21 行：

<style>
    ::slotted( span ) {
      text-decoration: underline!important
    }
</style>

以下是完整的片段：

//CREATE CUSTOM ELEMENT
class MyContact extends HTMLElement {
  constructor() {
     super()
    //retrieve template
    var tpl = document.querySelector('#contact-form-tpl');
    var tpl_ct = document.importNode(tpl.content, true);

    //this <=> my-contact element -> create shadow
    var shadowRoot = this.attachShadow( {mode:'open'}) //createShadowRoot();

    //show template in shadow DOM
    shadowRoot.appendChild(tpl_ct);
  }
}

//REGISTER CUSTOM ELEMENT
customElements.define("my-contact", MyContact);
span {
  text-decoration: line-through
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/document-register-element/1.11.0/document-register-element.js"></script>
<span>HELLO</span>
<!--line through by css at LINE 6: OK-->
<my-contact>
  <h1 slot=header>Contact X</h1>
  <span slot=name>this is my name</span>
  <span slot=phone>this is my phone</span>
</my-contact>


<template id="contact-form-tpl">
  <style>   
    span ::slotted( span ), 
    span { 
        text-decoration:underline!important  
    }
  </style>
  <fieldset>
    <legend>
      <slot name=header></slot>
      <div>
        Name: <span><slot name="name"></slot></span>
      </div>
      <div>
        Phone: <slot name="phone"><span></span></slot>
      </div>
      <span>TEST</span><!-- only apply css at line 21: OK-->
    </legend>
  </fieldset>
</template>

于 2018-07-16T22:03:59.260 回答