An example of a bootstrap JS script to inject Scala.js on any page load using browser extensions

browser-scalajs-inject.js

// You can inject any Scala.js component into any page using Chrome as follows:
// - This example references an arbitrary Scala.js package called bo-search
// - bo-search contains a top level definition BoSearch.initCit
// - Install CORS Unblock extension
// - Install Custom Style Script or Scripty extension
// - Disable CORS for the page
// - Setup a local web server to host this injection script
// - Use this script to inject the component into the page
var baseURL = "http://127.0.0.1:8080"
var injectUrl = baseURL + "/inject.js" // You can even just inject this URL
var targetUrl = baseURL + "/target/scala-2.13/scalajs-bundler/main"
var library = targetUrl + "/bo-search-fastopt-library.js"
var loader = targetUrl + "/bo-search-fastopt-loader.js"
var search = targetUrl + "/bo-search-fastopt.js"

function addScript(url, callback) {
    var script = document.createElement('script');
    script.onload = callback
    script.src = url;
    document.head.appendChild(script);
}

console.log("Injecting code")
addScript(library, function () {
    addScript(loader, function () {
        addScript(search, function () {
            console.log("Running code")
            // Hack to escape Scripty extensions JavaScript execution context
            var script = document.createElement("script");
            script.innerHTML = "window.BoSearch.initCit()";
            document.head.appendChild(script);
        })
    })
})