Executing [removed] elements inserted with [remove

Question

I've got a script that inserts some content into an element using innerHTML.

The content could for example be:

<script type="text/javascript">alert('test');</script>
<strong>test</strong>

Problem is that the code inside the <script> tag doesn't get executed. I googled it a bit but there were no apparent solutions. If I inserted the content using jQuery $(element).append(content);the script parts got eval'd before being injected into the DOM.

Has anyone got a snippet of code that executes all the <script> elements? The jQuery code was a bit complex so I couldn't really figure out how it was done.

Edit:

By peeking into the jQuery code I've managed to figure out how jQuery does it, which resulted in the following code:

Demo:
<div id="element"></div>

<script type="text/javascript">
  function insertAndExecute(id, text)
  {
    domelement = document.getElementById(id);
    domelement.innerHTML = text;
    var scripts = [];

    ret = domelement.childNodes;
    for ( var i = 0; ret[i]; i++ ) {
      if ( scripts && nodeName( ret[i], "script" ) && (!ret[i].type || ret[i].type.toLowerCase() === "text/javascript") ) {
            scripts.push( ret[i].parentNode ? ret[i].parentNode.removeChild( ret[i] ) : ret[i] );
        }
    }

    for(script in scripts)
    {
      evalScript(scripts[script]);
    }
  }
  function nodeName( elem, name ) {
    return elem.nodeName && elem.nodeName.toUpperCase() === name.toUpperCase();
  }
  function evalScript( elem ) {
    data = ( elem.text || elem.textContent || elem.innerHTML || "" );

    var head = document.getElementsByTagName("head")[0] || document.documentElement,
    script = document.createElement("script");
    script.type = "text/javascript";
    script.appendChild( document.createTextNode( data ) );
    head.insertBefore( script, head.firstChild );
    head.removeChild( script );

    if ( elem.parentNode ) {
        elem.parentNode.removeChild( elem );
    }
  }

  insertAndExecute("element", "<scri"+"pt type='text/javascript'>document.write('This text should appear as well.')</scr"+"ipt><strong>this text should also be inserted.</strong>");
</script>

Answer 1

It's easier to use jquery $(parent).html(code) instead of parent.innerHTML = code:

var oldDocumentWrite = document.write;
var oldDocumentWriteln = document.writeln;
try {
    document.write = function(code) {
        $(parent).append(code);
    }
    document.writeln = function(code) {
        document.write(code + "<br/>");
    }
    $(parent).html(html); 
} finally {
    $(window).load(function() {
        document.write = oldDocumentWrite
        document.writeln = oldDocumentWriteln
    })
}

This also works with scripts that use document.write and scripts loaded via src attribute. Unfortunately even this doesn't work with Google AdSense scripts.

Answer 2

Try this, it works for me on Chrome, Safari & Firefox:

var script = document.createElement('script');
script.innerHTML = 'console.log("hi")';
document.body.appendChild(script); 
--> logs "hi"

One thing to note though, is that the following div-nested script will NOT run:

var script = document.createElement('div');
script.innerHTML = '<script>console.log("hi")</script>';
document.body.appendChild(script);
--> doesn't log anything

For a script to run it has to be created as a node then appended as a child. You can even append a script inside a previously injected div & it will run (I've run into this before when trying to get ad server code to work):

var div = document.createElement('div');
div.id = 'test-id';
document.body.appendChild(div);
var script = document.createElement('script');
script.innerHTML = 'console.log("hi")';
document.getElementById('test-id').appendChild(script);
--> logs "hi"

Answer 3

Try function eval().

data.newScript = '<script type="text/javascript">//my script...</script>'
var element = document.getElementById('elementToRefresh');
element.innerHTML = data.newScript;
eval(element.firstChild.innerHTML);

This is a real example from a project that i am developing. Thanks to this post

Answer 4

Here's a shorter, more efficient script that also works for scripts with the src property:

function insertAndExecute(id, text) {
    document.getElementById(id).innerHTML = text;
    var scripts = Array.prototype.slice.call(document.getElementById(id).getElementsByTagName("script"));
    for (var i = 0; i < scripts.length; i++) {
        if (scripts[i].src != "") {
            var tag = document.createElement("script");
            tag.src = scripts[i].src;
            document.getElementsByTagName("head")[0].appendChild(tag);
        }
        else {
            eval(scripts[i].innerHTML);
        }
    }
}

Note: whilst eval may cause a security vulnerability if not used properly, it is much faster than creating a script tag on the fly.

Answer 5

You should not use the innerHTML property but rather the appendChild method of the Node: a node in a document tree [HTML DOM]. This way you are able to later call your injected code.

Make sure that you understand that node.innerHTML is not the same as node.appendChild. You might want to spend some time on the Javascript Client Reference for more details and the DOM. Hope the following helps...

Sample injection works:

<html>
<head>
<title>test</title>
<script language="javascript" type="text/javascript">
    function doOnLoad(){
        addScript('inject',"function foo(){ alert('injected'); }");
    }


    function addScript(inject,code){
        var _in = document.getElementById('inject');
        var scriptNode = document.createElement('script');
        scriptNode.innerHTML = code;
        _in.appendChild(scriptNode);
    }

</script>
</head>
<body onload="doOnLoad();">
    <div id="header">some content</div>
    <div id="inject"></div>
    <input type="button" onclick="foo(); return false;" value="Test Injected" />
</body>
</html>

regards,

Answer 6

Expending the answer of Lambder

document.body.innerHTML = '<img src="../images/loaded.gif" alt="" > onload="alert(\'test\');this.parentNode.removeChild(this);" />';

You can use base64 image to create and load your script

<img src="data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsMAAA7DAcdvqGQAAAAZdEVYdFNvZnR3YXJlAHBhaW50Lm5ldCA0LjAuMjHxIGmVAAAADUlEQVQYV2P4//8/AwAI/AL+iF8G4AAAAABJRU5ErkJggg=="
    onload="var script = document.createElement('script');  script.src = './yourCustomScript.js'; parentElement.append(script);" />

Or if you have a Iframe you can use it instead

<iframe src='//your-orginal-page.com' style='width:100%;height:100%'
    onload="var script = document.createElement('script');  script.src = './your-coustom-script.js'; parentElement.append(script);"
    frameborder='0'></iframe>