I have a web-component at root level. The simplified version of which is shown below:
class AppLayout {
constructor() {
super();
this.noShadow = true;
}
connectedCallback() {
super.connectedCallback();
this.render();
this.insertAdjacentHTML("afterbegin", this.navigation);
}
render() {
this.innerHTML = this.template;
}
get template() {
return `
<h1>Hello</h1>
`;
}
navigation = `
<script type="module">
import './components/nav-bar.js'
</script>
`;
}
customElements.define('app-layout', AppLayout);
I want to load a script after this component loads. The script creates html for navigation and tries to add it to the app-layout element shown above. However, even though, it does find the app-layout element, it is unable to append the navBar element. It is, however, able to append the navBar to the body of the html. Any ideas what I'm missing.
const navLinks =
`<ul>
<li>Some</li>
<li>Links</li>
</ul>
`;
const navBar = document.createElement('nav');
navBar.innerHTML = navLinks;
const appLayout = document.querySelector('app-layout'); // works with 'body' but not with 'appLayout'
console.log(appLayout); // Logs correct element
appLayout.appendChild(navBar);
I know that what I'm trying to do here (loading a script inside a web component) is not ideal, however, I would like to still understand why the above doesn't work.
using innerHTML or in your case insertAdjacentHTML to add <script> tags to the document doesn't work because browsers historically try to prevent potential cross site script attacks (https://www.w3.org/TR/2008/WD-html5-20080610/dom.html#innerhtml0)
What you could do is something like:
const s = document.createElement("script");
s.type = "module";
s.innerText = `import './components/nav-bar.js'`;
this.append(s);
// or simply directly without the script: `import('./comp..')` if it is really your only js in the script tag.
I am trying to add tracking script in .js file to my angular 12 application.
(function() {
var ds = document.getElementsByTagName("script")[0];
var dm = document.createElement("img");
dm.width = 1;
dm.height = 1;
dm.alt = " ";
dm.src = "https://example.com/url=" + window.location.href;
ds.parentNode.insertBefore(dm, ds);
})();
Script fires properly on the first page, but doesn't fire on navigating to another page on my website. When i check in elements window.location.href is not changing for the new page. It is because of SPA. How can i get latest location on all pages and script to fire on all pages
You could do it the Angular way, although idk if that will work.
You can go into your root component (should be AppComponent), and simply throw this inside the constructor or ngOnInit()
#Component({
...
})
export class AppComponent {
constructor(router: Router) {
router.events.pipe(
filter(route => route instanceof NavigationEnd),
concatMap((route) => ajax('https://example.com/url=' + route.url)),
).subscribe();
}
}
Unless you need your tracker to be an Img for some reason, or you get permission / CORS issues. This should work nicely
I'm building a dashboard using Dash in Python. I have configured all the graphs nicely (it's running on the server here) and the next step is to create a responsive navbar and a footer. Currently looks like this:
And when I shrink the width, it looks like this:
I want to add functionality to this button so it would hide the three links on click. I'm trying to toggle the CSS 'active' attribute using JavaScript with this piece of code:
var toggleButton = document.getElementsByClassName('toggle-button')[0]
var navBarLinks = document.getElementsByClassName('navbar-links')[0]
function toggleFunction() {
navBarLinks.classList.toggle('active')
}
toggleButton.addEventListener('click', toggleFunction)
Basically, when the navbar-links class is active, I want it to be set as display: flex, and when it's not active I want it to be display: none
The HTML elements defined in Python screen are here:
html.Nav([
html.Div('Covid-19 global data Dashboard', className='dashboard-title'),
html.A([html.Span(className='bar'),
html.Span(className='bar'),
html.Span(className='bar')],
href='#', className='toggle-button'),
html.Div(
html.Ul([
html.Li(html.A('Linked-In', href='#')),
html.Li(html.A('Source Code', href='#')),
html.Li(html.A('CSV Data', href='#'))
]),
className='navbar-links'),
], className='navbar')
I didn't expect that there would be issues with accessing elements through JavaScript. After doing some research I found out that JavaScript when executes getElementsByClassName function the returned value is null. That is because the function is run before the page is rendered (as far as I understand). It gives me this error:
This project is getting quite big, so I don't know which parts should I include in this post, but I will share the git repository and the preview of the page. Is there an easy solution to it?
You can defer the execution of JavaScript code until after React has loaded via the DeferScript component from dash-extensions. Here is a small example,
import dash
import dash_html_components as html
from html import unescape
from dash_extensions import DeferScript
mxgraph = r'{"highlight":"#0000ff","nav":true,"resize":true,"toolbar":"zoom layers lightbox","edit":"_blank","xml":"<mxfile host=\"app.diagrams.net\" modified=\"2021-06-07T06:06:13.695Z\" agent=\"5.0 (Windows)\" etag=\"4lPJKNab0_B4ArwMh0-7\" version=\"14.7.6\"><diagram id=\"YgMnHLNxFGq_Sfquzsd6\" name=\"Page-1\">jZJNT4QwEIZ/DUcToOriVVw1JruJcjDxYho60iaFIaUs4K+3yJSPbDbZSzN95qPTdyZgadm/GF7LAwrQQRyKPmBPQRzvktidIxgmwB4IFEaJCUULyNQvEAyJtkpAswm0iNqqegtzrCrI7YZxY7Dbhv2g3r5a8wLOQJZzfU4/lbByoslduPBXUIX0L0cheUrugwk0kgvsVojtA5YaRDtZZZ+CHrXzukx5zxe8c2MGKntNgknk8bs8fsj3+KtuDhxP+HZDVU5ct/RhatYOXgGDbSVgLBIG7LGTykJW83z0dm7kjklbaneLnEnlwFjoL/YZzb93WwNYgjWDC6EEdkuC0cZEO7p3i/6RF1WutL8nxmnkxVx6UcUZJIy/LgP49622mO3/AA==</diagram></mxfile>"}'
app = dash.Dash(__name__)
app.layout = html.Div([
html.Div(className='mxgraph', style={"maxWidth": "100%"}, **{'data-mxgraph': unescape(mxgraph)}),
DeferScript(src='https://viewer.diagrams.net/js/viewer-static.min.js')
])
if __name__ == '__main__':
app.run_server()
Dash callback solution (no Javascript):
import dash
import dash_html_components as html
from dash.dependencies import Output, Input, State
navbar_base_class = "navbar-links"
app = dash.Dash(__name__)
app.layout = html.Nav(
[
html.Div("Covid-19 global data Dashboard", className="dashboard-title"),
html.A(
id="toggle-button",
children=[
html.Span(className="bar"),
html.Span(className="bar"),
html.Span(className="bar"),
],
href="#",
className="toggle-button",
),
html.Div(
id="navbar-links",
children=html.Ul(
children=[
html.Li(html.A("Linked-In", href="#")),
html.Li(html.A("Source Code", href="#")),
html.Li(html.A("CSV Data", href="#")),
],
),
className=navbar_base_class,
),
],
className="navbar",
)
#app.callback(
Output("navbar-links", "className"),
Input("toggle-button", "n_clicks"),
State("navbar-links", "className"),
prevent_initial_call=True,
)
def callback(n_clicks, current_classes):
if "active" in current_classes:
return navbar_base_class
return navbar_base_class + " active"
if __name__ == "__main__":
app.run_server(debug=True)
The idea of the code above is to take the toggle-button click as Input and the current value of navbar-links as State. We can use this state to determine if we should add the active class or remove it. The new className value is returned in the callback.
Javascript solution:
window.addEventListener("load", function () {
var toggleButton = document.getElementsByClassName("toggle-button")[0];
var navBarLinks = document.getElementsByClassName("navbar-links")[0];
function toggleFunction() {
navBarLinks.classList.toggle("active");
}
toggleButton.addEventListener("click", toggleFunction);
});
The load event is fired when the whole page has loaded, including all dependent resources such as stylesheets and images. This is in contrast to DOMContentLoaded, which is fired as soon as the page DOM has been loaded, without waiting for resources to finish loading.
https://developer.mozilla.org/en-US/docs/Web/API/Window/load_event
DOMContentLoaded would be preferable to use, but it only works for me with load.
If you need a pure JS solution you need to use MutationObserver. I've wrote a little helper function we are currently using that did the trick. Another suggestion would be to change the mutation to an element on screen then fire an event to handle the rest
/**
*
* #param {string} id
* #param {*} event
* #param {(this: HTMLElement, ev: any) => any} callback
* #param {boolean | AddEventListenerOptions} options
*/
function attachEventToDash(id, event, callback, options) {
debugger;
var observer = new MutationObserver(function (_mutations, obs) {
var ele = document.getElementById(id);
if (ele) {
debugger;
ele.addEventListener(event, callback, options)
obs.disconnect();
}
});
window.addEventListener('DOMContentLoaded', function () {
observer.observe(document, {
childList: true,
subtree: true
});
})
}
I'm trying to create a React Portal that when mounted, requires running a specific line to load an ActiveReports Designer component.
Here's is my portal code:
constructor(props: IWindowPortalProps) {
super(props);
this.containerEl = document.createElement('div'); // STEP 1: create an empty div
this.containerEl.id = 'designer-host';
this.containerEl.className = styles.designerHost;
this.externalWindow = null;
}
private copyStyles = (sourceDoc: Document, targetDoc: Document) => {
Array.from(sourceDoc.styleSheets).forEach(styleSheet => {
if (styleSheet.cssRules) { // true for inline styles
const newStyleEl = sourceDoc.createElement('style');
Array.from(styleSheet.cssRules).forEach(cssRule => {
newStyleEl.appendChild(sourceDoc.createTextNode(cssRule.cssText));
});
targetDoc.head.appendChild(newStyleEl);
} else if (styleSheet.href) { // true for stylesheets loaded from a URL
const newLinkEl = sourceDoc.createElement('link');
newLinkEl.rel = 'stylesheet';
newLinkEl.href = styleSheet.href;
targetDoc.head.appendChild(newLinkEl);
}
});
}
componentDidMount() {
this.externalWindow = window.open('', '', `height=${window.screen.height},width=${window.screen.width}`);
this.externalWindow.document.body.appendChild(this.containerEl);
this.externalWindow.document.title = 'A React portal window';
this.externalWindow.addEventListener('load', () => {
new Designer('#designer-host');
});
}
render() {
return ReactDOM.createPortal(null, this.containerEl);
}
However, when the new window loads, I get the error
Error: Cannot find the host element. at Function.<anonymous>
which indicates that the designer-host div is not there. I think the load function points to the main DOM and not the new window's one.
Alternatively, I tried appending the ActiveReports .js file by doing in my componentDidMount()
s.type = "text/javascript";
s.src = "../node_modules/#grapecity/activereports/lib/node_modules/#grapecity/ar-js-designer/index.js";
this.externalWindow.document.head.append(s);
and then assigning the Designer instantiation on the onLoad property of the element. Again with no luck.
Is there maybe a way I could run JavaScript a code after the portal has been loaded and point to that DOM?
Thank you
I work for GrapeCity. Could you please go to our support portal and submit a ticket. We will need a full code sample for us to be able to answer this question. Please give us a download link to the sample within the ticket.
Thank you
I am trying to test this piece of HTML generated by React JS:
<div class="media-img">
<img src='images-name.jpg' />
</div>
As you can see, the image has no class name, and I can't put one on. I am using Jasmine to try and test that the src of the image is correct. But I can't seem to get hold of the image element in React. In jQuery this would be really easy, I could use $('.media-img img'), is there a way to traverse the DOM in React?
This is what I have so far:
var React = require('react'),
TestUtils = React.addons.TestUtils,
Component = require('component'),
renderedComponent;
function renderComponent(data) {
data = data || {};
renderedComponent = TestUtils.renderIntoDocument(
React.createElement(Component, data)
);
}
var imageURL = 'http://lorempixel.com/g/400/200/',
image,
imageSection;
renderComponent({
src: imageURL
});
imageSection = TestUtils.scryRenderedComponentsWithType(renderedComponent, 'media-img');
image = TestUtils.findRenderedDOMComponentWithTag(imageSection, 'img');
expect(image.src).toBe(imageURL);
But it isn't working. It seems that you can't pass a React component into another as I've tried to do at the bottom. So how can you traverse the virtual DOM?
I found an answer. Instead of attempting to pass a React component into another to test a subsection of the rendered DOM, I looked through the entire rendered DOM for 'img'. Normally this would be a bit inefficient as the rendered DOM could be huge and full of 'img' tags, but as this is a unit test with limited data, the rendered DOM is small and predictable. I used this:
image = TestUtils.findRenderedDOMComponentWithTag(renderedContributor, 'img');
Then I didn't need the 'imageSection' variable at all. Then I could call the DOM Node, then look at its 'src', by adding:
image.getDOMNode().src;
So my complete amended code looks like this:
var React = require('react'),
TestUtils = React.addons.TestUtils,
Component = require('component'),
renderedComponent;
function renderComponent(data) {
data = data || {};
renderedComponent = TestUtils.renderIntoDocument(
React.createElement(Component, data)
);
}
var imageURL = 'http://lorempixel.com/g/400/200/',
image;
renderComponent({
src: imageURL
});
image = TestUtils.findRenderedDOMComponentWithTag(renderedComponent, 'img');
expect(image.getDOMNode().src).toBe(imageURL);