eval() doesn't execute external (src=...) scripts

Question

I'm using eval() to execute all <script> tags after total rewrite of a div (whose code is loaded via an XMLHttpRequest):

var arr = document.getElementById('idOfDIV').getElementsByTagName('script');
         for (var n = 0; n < arr.length; n++){
                try {
                 eval(arr[n].innerHTML);
                } catch(err) {
                console.log(err);
                }
        }

It works well for inline-scripts, but has no effect on scripts like:

<script src="/path/to/externalScript.js"></script>

How come? Can I "force" the browser to load and execute also the external scripts?

NOTE: As I noted, the question may seems "strange", regarding the fact that eval() executes a string as javascript. What I need to do, is the force the browser to load external scripts contained in "pasted" DOM, and execute them.

um you can't really do that since the script tags don't have the source in the HTML. you could add the script tags again but that could cause a lot of leaks. — Daniel A. White, Jan 23 '15 at 13:43
I'm not clear what you're trying to do -- `eval()` runs a string as executable JavaScript code, it doesn't do anything with HTML tags. If you were using jQuery, I'd suggest the [`$.getScript()`](http://api.jquery.com/jquery.getscript/) method. — Blazemonger, Jan 23 '15 at 13:45
@Blazemonger: You're right, I'm updating the question with a note — Carmine Giangregorio, Jan 23 '15 at 13:47
Incidentally, this is part of the reason why separation of concerns is a good idea -- HTML and JavaScript shouldn't be intertwined this much in the first place. I'd suggest taking all the scripts out of that `div` and combining them together somewhere else in a single function. — Blazemonger, Jan 23 '15 at 13:48
`eval` is meant to evaluate **JavaScript** code, **not HTML**. — plalx, Jan 23 '15 at 13:49
@plalx: I know... As I already stated, I need to have the script retrieved and then executed via eval() — Carmine Giangregorio, Jan 23 '15 at 13:50
Use AJAX to retrieve the external file if there's an `src` attribute, and `eval()` whatever you get. — Blazemonger, Jan 23 '15 at 13:51
eval is evaluating Javascript in this code, as `arr` is a list of — Hacketo, Jan 23 '15 at 13:52

Hacketo · Answer 1 · 2015-01-23T14:27:51.247

This tag :

<script src="/path/to/externalScript.js"></script>

has empty innerHTML, so you cant eval the content

What you could do is to check if the script has an src attribute, and add a script tag in the head with this src :

function addHeadScript = function(src){
    var head = document.getElementsByTagName("head")[0];
    var script = document.createElement("script");
    script.type = "text/javascript";
    script.src = src;
    head.appendChild(script);
}

...


for (var n = 0; n < arr.length; n++){
    if (arr[n].src != ""){
        addHeadScript(arr[n].src);
    }
    else {
        // Evaluate the script `innerHTML`   OR
        // Create a script tag in the head and set it's content equal to arr[n].innerHTML
    }
}

score 2 · Answer 2 · answered Jan 23 '15 at 15:01

Here's one thing you could do:

var html = "Some html with a script <script>alert('test');</script>";

var frag = parsePartialHtml(html);

fixScriptsSoTheyAreExecuted(frag);


document.body.appendChild(frag);


function fixScriptsSoTheyAreExecuted(el) {
  var scripts = el.querySelectorAll('script'),
      script, fixedScript, i, len;

  for (i = 0, len = scripts.length; i < len; i++) {
    script = scripts[i];

    fixedScript = document.createElement('script');
    fixedScript.type = script.type;
    if (script.innerHTML) fixedScript.innerHTML = script.innerHTML;
    else fixedScript.src = script.src;
    fixedScript.async = false;

    script.parentNode.replaceChild(fixedScript, script);
  }
}


function parsePartialHtml(html) {
  var doc = new DOMParser().parseFromString(html, 'text/html'),
      frag = document.createDocumentFragment(),
      childNodes = doc.body.childNodes;

  while (childNodes.length) frag.appendChild(childNodes[0]);

  return frag;
}

eval() doesn't execute external (src=...) scripts

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