Javascript, execute scripts code in order inserted into dom tree

Question

NOT A DUPLICATE AS I HAVE YET TO FOUND A SATISFYING ANSWER ON OTHER THREADS:

• Load and execute javascript code SYNCHRONOUSLY
• Loading HTML and Script o

Answer 1

I am posting here just like a draft
This do not work because cross-domain police
Here the idea is to obtain all scripts first and when they are in memory, execute them in order.

function loadScript(order, path) {
    var xhr = new XMLHttpRequest();
    xhr.open("GET",path,true);
    xhr.send();
    xhr.onreadystatechange = function(){
        if(xhr.readyState  == 4){
            if(xhr.status >= 200 && xhr.status < 300 || xhr == 304){
                loadedScripts[order] = xhr.responseText;
            }
            else {
                //deal with error
                loadedScripts[order] = 'alert("this is a failure to load script '+order+'");';
                // or  loadedScripts[order] = '';  // this smoothly fails
            }
            alert(order+' - '+xhr.status+' > '+xhr.responseText);                // this is to show the completion order.  Careful, FF stacks aletrs so you see in reverse.
            // am I the last one ???
            executeAllScripts();
        }
    };
}

function executeAllScripts(){
    if(loadedScripts.length!=scriptsToLoad.length) return;
    for(var a=0; a