将参数/输入数据传递到javascript中的自定义元素 [英] passing parameter/input data to custom elements in javascript

问题描述

我正在尝试实现与此代码相同的代码使用JavaScript，因此将以下代码写为btn.js文件:

I'm trying to implement the same code of this using JavaScript, so wrote the below code as btn.js file:

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

// Set up the element.
SaveBtn.createdCallback = function() {
// Create a Shadow Root
var shadow = this.createShadowRoot();
this.type='button';

// Add an event listener to the image.
this.addEventListener('click', function(e) {
    alert('got a click');
    document.getElementById("ShowButton").value= "Hide Filter";
 });
};

// Register the new element.
var Xbtn =document.registerElement('save-button', {
prototype: SaveBtn,
extends: 'input'
});

并在另一个main.js函数中调用它，如下所示:

and called it in the other function main.js as below:

window.addEventListener("load", onLoad, false);

 function onLoad() {
     var host = document.querySelector('#host');
     var el = new Xbtn();
     host.appendChild(el);
 }

这很好用，并给了我毯子按钮.

this worked fine, and gave me blanket button.

现在我想将要显示的文本"传递到按钮中，我尝试了以下操作:

now I want to pass the 'text' to be displayed into the button, I tried the below:

在index.html中，我已经:

in the index.html I've:

  <div id="host"></div>

 <input  id="ShowButton" type="button" value="Show Filter"/>

在main.js中:

el.value = 'click me';

以及btn.js:

this.value = this.getAttribute('text');

但失败，并且按钮仍然为空！考虑到单击后其他按钮的值已更改

but failed, and the button still empty! considering that the other button value is changed upon the click

有什么想法吗?

推荐答案

仅在定义的功能范围内可以访问影子DOM根.您要么需要将影子DOM根对象分配给外部作用域变量，要么需要公开操作影子DOM的作用域内函数.由于您要操纵多个元素的影子DOM，因此在每个实例上使用setter函数是最佳选择.

The shadow DOM root is only accessible within the function-scope it is defined. You either need to assign the shadow DOM root object to an outer-scope variable, or you need to expose an in-scope function that manipulates the shadow DOM. Since you want to manipulate the shadow DOM for multiple elements, a setter function on each instance is the best option.

您可以完全公开影子DOM:

You can expose the shadow DOM entirely:

SaveBtn.createdCallback = function() {
    var shadow = this.createShadowRoot();
    this.myShadow = shadow;
    //...
}

...

el.myShadow.textContent = "click me";

但是，由于影子DOM的一个主要功能是能够隐藏DOM组件，使其不受其他脚本的操纵，因此，您可能希望拥有一个setter函数，例如，该函数可以验证输入并在内部执行该操纵:

However, since a major feature of the shadow DOM is being able to hide DOM components from manipulation by other scripts, you may instead wish to have a setter function that (for example) validates input and performs the manipulation internally:

SaveBtn.createdCallback = function() {
    var shadow = this.createShadowRoot();

    this.setShadowText = function(text) {
        shadow.textContent = text;
    }
    //...
}

...

el.setShadowText("click me");

这篇关于将参数/输入数据传递到javascript中的自定义元素的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！