javascript - 使用javascript在自定义元素中设置主机样式

Question

我写了下面的代码来获得一个带有文本和按钮的阴影 DOM，文本和按钮的样式都正确，而主机背景的样式却很奇怪，

代码是:

 // Create a new object based of the HTMLElement prototype
 var fonixDiv = Object.create(HTMLElement.prototype);

// Set up the element.
fonixDiv.createdCallback = function() {
// Create a Shadow Root
var shadow = this.createShadowRoot();
    shadow.innerHTML = '\
                        <style>\
                        :host { \
                         border: 2px dashed red;\
                         text-align: left;\
                         font-size: 28px;\
                         background: blue;\
                         }\
                          h3 { color: red; }\
                          button { color: green; }\
                        </style>\
                        <h3>Shadow DOM</h3>\
                        <button id="d">click</button>\
                        ';
      shadow.children.d.addEventListener('click', function(e) {
        this.textContent = "you clicked me :(";
        shadow.children[1].textContent="Shadow DOM content changed";
        host.style.background = "green";
        alert("All: button, text and host should be change");
  });
};

输出在附件中。

请帮忙。

Answer 1

我能够使用 css 文件解决问题:

.html 文件是:

<fonix-div></fonix-div>
<div id="host1"></div>

.js 文件是:

// Create a new object based of the HTMLElement prototype
var fonixDiv = Object.create(HTMLElement.prototype);

// Set up the element.
fonixDiv.createdCallback = function() {

// Create a Shadow Root
var shadow = this.createShadowRoot();

    shadow.innerHTML = '<button id="d">click</button>';

       shadow.addEventListener('click', function(e) {
            console.log('1: '+this.host.dataset.disabled);
            this.host.dataset.disabled='true';   // set Attribute to the custom element
       });

       shadow.children.d.addEventListener('click', function(e) {
            this.textContent = "you clicked me :(";
            shadow.children[1].textContent="Shadow DOM content changed";
            this.disabled=true;
            alert("All: button, text and host should be change");
       });
};

// Register the new element.
var Xfonix =document.registerElement('fonix-div', {prototype: fonixDiv});

var thehost = document.querySelector('#host1');
thehost.appendChild(new Xfonix());

.css 文件是:

body {background: #F7F7F7;}

fonix-div {
  display: inline-block;
  width: 200px;
  height: 200px;  
  float: left;
  margin: 0.5em;
  border-radius: 3px;
  background: #FFF;
  box-shadow: 0 1px 3px rgba(0,0,0,0.25);
  font-family: Helvetica, arial, sans-serif;
  -webkit-font-smoothing: antialiased;
    }

fonix-div:hover, fonix-div[data-disabled='true']:hover {background: red;}

fonix-div:Active {background: green;}

fonix-div[data-disabled='true'] {background: green;}

fonix-div::shadow p{color: blue;}

可以看到输出here: