What is the IFRAME advantage over shadowDOM?

[Danny-Engelman]

With a <load-file> Web Component you have the choice of loading any content into DOM, or in shadowDOM to keep <style> scoped... and even move (global) style (or any Node for that matter) to shadowDOM
No need to define it before being used like your htmz function; any existing <load-file> will upgrade automagically.

/*
  defining the <load-file> Web Component,
  yes! the documenation is longer than the code
  License: https://unlicense.org/
*/
customElements.define("load-file", class extends HTMLElement {

  // declare default connectedCallback as async so await can be used
  async connectedCallback(
    // call connectedCallback with parameter to *replace* SVG (if <load-file> is not replaceWith)
    src = this.getAttribute("src"),
    // attach a shadowRoot if none exists (prevents displaying error when moving Nodes)
    // declare as parameter to save 4 Bytes: 'let '
    shadowRoot = this.shadowRoot || this.attachShadow({mode:"open"})
  ) {
      // load SVG file from src="" async, parse to text, add to shadowRoot.innerHTML
    shadowRoot.innerHTML = await (await fetch(src)).text()

    // append optional <tag [shadowRoot]> Elements from <load-file> innerHTML/lightDOM after parsed content
    shadowRoot.append(...this.querySelectorAll("[shadowRoot]"))

    // if "replaceWith" attribute exists
    // then replace <load-file> with loaded content <load-file>
    // childNodes instead of children to include #textNodes also
    this.hasAttribute("replaceWith") && this.replaceWith(...shadowRoot.childNodes)
  }
})

source: a DEV.to Post from 2021

[lpil]

A lot more code, but looks interesting!

Could you share how I could have an a element load content into another element using this code? The same way that htmz does.

Thank you.

[Danny-Engelman]

You don't have to load it in another element, <load-file> is the element

[lpil]

That means one can't use it to do what htmz does, so it's not an alternative.

[Danny-Engelman]

Or replace shadowRoot = this.shadowRoot || this.attachShadow({mode:"open"})

with shadowRoot = document.getElementById( this.getAttribute("for") )

And do <load-file src="..." for="myId">

its only modern JavaScript...

[lpil]

Hi @Danny-Engelman ! That isn't enough to replace htmz I'm afraid. You'd need some additional system for handling form submissions, links, and buttons to load new content into some other element.

[Kalabasa]

Hi, htmz works on click.

<load-file> solves a slightly different problem which is more like client-side includes / HTML imports (HTML proposal: whatwg/html#2791).

As others have mentioned, the advantage of iframes is that they can be targeted with regular HTML, so it works with native elements like forms, links, and buttons.

Converting to Discussion.