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Dynamically added javascript with external script doesn't get executed

 原文  2016-07-20 08:49:06  5   7    javascript/ html/ dom

Question

So this is our scenario... First thing we do is, we append a piece of javascript code which adds external script to document like this: 

(function() {
     var e = document.createElement('script'); e.type = 'text/javascript'; e.async = true; e.src = 'http://blabla.com/script.js';
     var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(e, s);
})();

Then in script.js following happens: 

function ajaxCall() { 
    //... some script to send ajax request which calls createDiv() after success
   if (window.XMLHttpRequest){
      xmlhttp=new XMLHttpRequest();
   }
   else{
      xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
   }
   xmlhttp.onreadystatechange=function(){
      if(xmlhttp.readyState==4&&xmlhttp.status==200){
         createDiv(xmlhttp.responseText);
      }
   };
   xmlhttp.open("GET","http://blabla.com/api/");
   xmlhttp.send(); 
}
function parseResponse(response) {
    var parser = new DOMParser();
    var dom = parser.parseFromString(response, "text/html");
    return dom;
}
function createDiv(responsetext)
{
   var dom = parseResponse(responsetext);

   var _ws = dom.getElementById('styles');
   var h = document.getElementsByTagName('head')[0];
   h.appendChild(document.importNode(_ws, true));

   var _jr = dom.getElementById('script1').outerHTML;
   var _vc = dom.getElementById('script2').outerHTML;
   var _rv = dom.getElementById('script3').outerHTML;

   var _rw = dom.getElementById('my_div');
   var _b = document.getElementsByTagName('body')[0];
   var _d = document.createElement('div'); _d.id = 'just_id';
   _d.innerHTML = _jr + _vc + _rv;
   _d.appendChild(document.importNode(_rw, true));
   _b.appendChild(_d);
}
ajaxCall();

Everything works fine, script's and a div are being appended as expected and where expected, but appended script doesn't get executed and doesn't affect appended div . Why is that? And how can I make it execute? We also don't get any warnings/errors in console. Using latest firefox.

EDIT 1

Comment: The example script you showed just defines function, but it never actually calls them

It actually calls a function which makes an ajax request, please check edited code snippet.

EDIT 2

Comment: Have you tried to put the logic in a callback and then call it in createDiv? May be add some logs to test if its getting called but it unable to find div

I just tried console.log('hello world'); call in one of scripts which are being appended by createDiv() function, but it does nothing.

EDIT 3

For more details. When page is loaded, I can see 

<script type="text/javascript" id="script1" src="http://blabla.com/script1.js"></script>
<script type="text/javascript" id="script2" src="http://blabla.com/script2.js"></script>
<script type="text/javascript" id="script3" src="http://blabla.com/script3.js"></script>
<div id="just_id">Content here</div>

In DOM-Inspector and as mentioned above, there is console.log('hello world'); to test it, but it doesnt get executed.

EDIT 4

Added some CSS through createDiv() function to document's <head></head> and it affects my div with id 'just_id'. JS still isn't working.

EDIT 5

Also tried to append inline javascript instead of external one in my function, but still no success. Can see following in DOM-Inspector, but code doesn't log anything. 

<script type="text/javascript">
   console.log('test');
</script>

EDIT 6

I also tried to import nodes from as suggested here

This method is not allowed to move nodes between different documents. If you want to append node from a different document the document.importNode() method must be used.

and also tried to changed order. 1.css 2.div 3.js like this but still no success... Anyone has an idea what is going on here?

Check the code above

EDIT 7

As suggested in How do you execute a dynamically loaded JavaScript block? I set innerHTML of my div to scripts + content and then appended to DOM like this:

Check the code above

But still without any success.

EDIT 8

Added ajax function code. 3rd paramter in xmlhttp.open("GET","http://blabla.com/api/"); true (asynchronous) and false (synchronous) already tried. Still no success.

EDIT 9

function createDiv() as suggested in answer: 

var dom = parseResponse(responsetext);

var _jr = dom.getElementById('script1'); //<script> tag with src attribute
var _vc = dom.getElementById('script2'); //inline <script> for test purposes only, it should actualy be external script also
var _rv = dom.getElementById('script3'); //inline <script>

var _rw = dom.getElementById('external_div');
var _b = document.getElementsByTagName('body')[0];
var _d = document.createElement('div'); _d.id = 'internal_div';
_d.appendChild(document.importNode(_rw, true));
_d.appendChild(document.importNode(_jr, true));
_d.appendChild(document.importNode(_rv, true)); //without second parameter TRUE, I dont get script content
_d.appendChild(document.importNode(_vc, true)); //without second parameter TRUE, I dont get script content
_b.appendChild(_d);

Doesn't work. Work's only if I take innerHTML of inline scripts from other document, create elements like suggested in answer, set their innerHTML and then append do current document. External script's wont load at all.

EDIT 10

.htaccess from localhost... : 

<Files *.html>
    Order Deny,Allow
    Deny from all
    Allow from 127.0.0.1
</Files>

<Files *.php>
    Order Deny,Allow
    Deny from all
    Allow from 127.0.0.1
</Files>

<Files index.php>
    Order Allow,Deny
    Allow from all
</Files>

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /page1/
#RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-l
RewriteRule ^(.+)$ index.php?url=$1 [QSA,L]
</IfModule>

.htaccess from 192.*** ... : 

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /direktexpress/
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /page2/index.php [L]
</IfModule>
# END WordPress

EDIT 11

So I am probably going to give bounty @Drakes, just for the effort and his spent time on my question and going to show some screenshots what is going on. It is definitely firefox bug, I just tested on chrome and it works.

1st picture: source code of 192.168.2.197/testing/whatever/etc. .htaccess remains the same as in example above

源代码192.168.2.197

2nd picture is source code for script.js, which is being loaded on 192.168.2.197/testing/whatever/etc. .htaccess remains the same as in example above:

Script.js来源

3rd picture is a screenshot of inspector, how does my dom look like:

大教堂

4th picture.... nothing happens. Just a warning which has nothing to do with my problem (I hope so), because even when I remove all scripts, it still appears.

安慰

Is it a firefox bug?

7 answers

solution1
 8  2016-07-22 19:01:41

The problem is that the code above is mixing appendChild with innerHTML . It's not intuitively obvious that the two perform differently in some cases. The former allows newly inserted script nodes to be executed as they are attached to the DOM. The latter doesn't. This has been a head-scratcher for many people. Kindly Google "script and innerHTML" and you will find that you are not alone facing this similar problem.

If you (1) change 

_d.innerHTML = _jr + _vc + _rv

to 

_d.appendChild(document.importNode(_jr));
_d.appendChild(document.importNode(_vc));
_d.appendChild(document.importNode(_rv));

and additionally (2) change 

var _jr = dom.getElementById('script1').outerHTML;
var _vc = dom.getElementById('script2').outerHTML;
var _rv = dom.getElementById('script3').outerHTML;

to 

var _jr = dom.getElementById('script1');
var _vc = dom.getElementById('script2');
var _rv = dom.getElementById('script3');

then your scripts will get executed. Here is a demonstration: 

 var b = document.getElementsByTagName('body')[0]; /* Works */ var s1 = document.createElement('script'); s1.innerHTML = "console.log('I will execute')"; b.appendChild(s1); /* Fails */ var s2 = document.createElement('script'); s2.innerHTML = "while(1){alert('Do not worry! I will not execute');}"; b.innerHTML = s2.outerHTML; console.log("It didn't execute");

Tested

I ran the OP's code on my server to replicate the problem as best I can. Given the supplied code I can make it work as intended on my server. I only changed the AJAX URL from http://blabla.com/api/ to api.html and supplied my own file as none was provided by the OP, but I pieced together what it should contain from the OP's JavaScript). Here are sample results:

index.html 

<html lang="en">
<body>
    <script>
        (function() {
            var e = document.createElement('script'); e.type = 'text/javascript'; e.async = true; e.src = 'script.js';
            var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(e, s);
        })();
    </script>
</body>
</html>

script.js

This is the OP's code modified to my specifications above (using appendChild instead of innerHTML , and the AJAX call returns the contents of api.html below) 

function ajaxCall() {
    //... some script to send ajax request which calls createDiv() after success
    if (window.XMLHttpRequest){
        xmlhttp=new XMLHttpRequest();
    }
    else{
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange=function(){
        if(xmlhttp.readyState==4&&xmlhttp.status==200){
            createDiv(xmlhttp.responseText);
        }
    };
    xmlhttp.open("GET","api.html");
    xmlhttp.send();
}
function parseResponse(response) {
    var parser = new DOMParser();
    var dom = parser.parseFromString(response, "text/html");
    return dom;
}
function createDiv(responsetext)
{
    var dom = parseResponse(responsetext);

    var _ws = dom.getElementById('styles');
    var h = document.getElementsByTagName('head')[0];
    h.appendChild(document.importNode(_ws, true));

    var _jr = dom.getElementById('script1');
    var _vc = dom.getElementById('script2');
    var _rv = dom.getElementById('script3');

    var _rw = dom.getElementById('my_div');
    var _b = document.getElementsByTagName('body')[0];
    var _d = document.createElement('div'); _d.id = 'just_id';

    _d.appendChild(document.importNode(_jr, true));
    _d.appendChild(document.importNode(_vc, true));
    _d.appendChild(document.importNode(_rv, true));

    _d.appendChild(document.importNode(_rw, true));
    _b.appendChild(_d);
}
ajaxCall();

api.html (returned by the AJAX call) 

<!DOCTYPE html>
<html>
<body>
    <style type="text/css" id="styles"></style>
    <script type="text/javascript" id="script1" src="script1.js"></script>
    <script type="text/javascript" id="script2">console.log("incline script 2")</script>
    <script type="text/javascript" id="script3">console.log("incline script 3")</script>
    <div id="my_div"></div>
</body>
</html>

script1.js 

console.log("src script1");

Here are the DevTools results to show this is working.

开发工具检查

控制台结果

solution2
 4  2016-07-25 15:54:29

The JavaScript of the page has already been parsed, you need to eval the result to put it into the window context. 

function evalRequest(url) {
    var xmlhttp = new XMLHttpRequest();
    xmlhttp.onreadystatechange = function() {
        if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
            eval(xmlhttp.responseText);
        }
    }
    xmlhttp.open("GET", url, true);
    xmlhttp.send(null);
};

UPDATE : you might need to get the script as text and then eval it ) 

function getScriptsAsText() {
    var div = document.createElement('div');
    var scripts = [];
    var scriptNodes = document.getElementsByTagName('script');

    for (var i = 0, iLen = scriptNodes.length; i < iLen; i++) {
        div.appendChild(scriptNodes[i].cloneNode(true));
        scripts.push(div.innerHTML);
        div.removeChild(div.firstChild);
    }
    return scripts;
};

solution3
 0  2016-07-25 10:34:50

You are currently loading a script into your page. This happens AFTER the page js was already executed (since is async and usually loading an external resource takes longer than the script execution).

So... basically you have the right function definitions and everything, and calling them from console later should work (I think you already tried that and was fine).

Still, the calls to your functions, even thought they are there won't execute since will not be computed after load.

To work around this, you can create an ajax request to a page that has the script, and in its callback to call whatever function you need to call.

solution4
 0  2016-07-27 09:13:06

我会说删除异步，因为操作在初始页面加载后出现

solution5
 0  2016-07-27 22:00:31

    (function () {
        var s = document.getElementsByTagName('script')[0];
        s.parentNode.insertBefore(CreateScriptTag('http://blabla.com/script.js',true), s);
    })();
    function CreateScriptTag(src, isAsync) {
        var e = document.createElement('script')
        e.type = 'text/javascript';
        e.async = isAsync;
        e.src = src;
    return e;
    }
    function ajaxCall() {
        //... some script to send ajax request which calls createDiv() after success
        if (window.XMLHttpRequest) xmlhttp = new XMLHttpRequest();
        else  xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
        xmlhttp.open("GET", "http://blabla.com/api/");
        xmlhttp.onreadystatechange = function () { if (xmlhttp.readyState === 4 && xmlhttp.status === 200) createDiv(xmlhttp.responseText); };
        xmlhttp.send();
    }
    function parseResponse(response) {
        var parser = new DOMParser();
        var dom = parser.parseFromString(response, "text/html");
        return dom;
    }
    function createDiv(responsetext) {
        var head=document.getElementsByTagName('head')[0],dom = parseResponse(responsetext),_div=document.createElement('div');
        head.appendChild(document.importNode(dom.getElementById('styles'), true)); //Assuming stylesheets are working fine.
        _div.id = 'just_id';
        //div.innerHTML = _script1 + _script2 + _script3;
        document.getElementsByTagName('body')[0].appendChild(_div.appendChild(dom.getElementById('my_div')));

        head.appendChild(CreateScriptTag(dom.getElementById('script1').getAttribute("src"),true));
        head.appendChild(CreateScriptTag(dom.getElementById('script2').getAttribute("src"),true));
        head.appendChild(CreateScriptTag(dom.getElementById('script3').getAttribute("src"),true));

    /* or another idea;
        document.write(_script1 + _script2 + _script3);
    */
    }
    ajaxCall();

solution6
 0  2016-07-28 14:00:28

The problem is your method is asynchronous not synchronous execution. Meaning the page is still loading while you insert your dynamical scripts. There are few ways to do so:

  1. The easiest way is to use jQuery $(document).append instead of document.createElement, if you don't mind using the library.

  2. You can also use jQuery $.getScript .

  3. If you prefer not to include 3rd libraries, you have to think of a way to delay page load while you insert your scripts, something like an alert to creat a prompt window will work, but user experience not so good, think of a more smooth way.

  4. Use XMLHTTPRequest to retrieve your scripts. This is synchronous and I can see you are familiar with it because you are using it in your script already.

Good luck and happy coding.

solution7
 0  2016-07-28 22:47:50

Have you tried getting the URL of the src file and excuting it with jQuery's getScript() function?

Change your creatediv() function : 

var _jr = dom.getElementById('script1').outerHTML;

var srcScript1Left = _jr.split('src="');
srcScript1Right = srcScript1Left[1].split('"');
srcScript1 = srcScript1Right[0];

console.log(srcScript1);

$.getScript(srcScript1, function()
{
    // The external script has been executed.
});

EDIT

Similar method in pure Javascript : 

var _jr = dom.getElementById('script1').outerHTML;

var srcScript1Left = _jr.split('src="');
srcScript1Right = srcScript1Left[1].split('"');
srcScript1 = srcScript1Right[0];

console.log(srcScript1); // Display the name of the external script file

if(window.XMLHttpRequest) {
    xmlhttp=new XMLHttpRequest();
} else {
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function() {
    if(xmlhttp.readyState == 4 && xmlhttp.status == 200) {
        eval(xmlhttp.responseText); // Execute the external script
    }
};
xmlhttp.open("GET",srcScript1);
xmlhttp.send();

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