Is it possible to append to innerHTML without destroying descendants’ event listeners?

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In the following example code, I attach an onclick event handler to the span containing the text “foo”. The handler is an anonymous function that pops up an alert().

However, if I assign to the parent node’s innerHTML, this onclick event handler gets destroyed – clicking “foo” fails to pop up the alert box.

Is this fixable?

<html>
 <head>
 <script type="text/javascript">

  function start () {
    myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    mydiv = document.getElementById("mydiv");
    mydiv.innerHTML += "bar";
  }

 </script>
 </head>

 <body onload="start()">
   <div id="mydiv" style="border: solid red 2px">
     <span id="myspan">foo</span>
   </div>
 </body>

</html>

First answer

Unfortunately, assignment to innerHTML causes the destruction of all child elements, even if you’re trying to append. If you want to preserve child nodes (and their event handlers), you’ll need to use DOM functions:

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    mydiv.appendChild(document.createTextNode("bar"));
}

Edit: Bob’s solution, from the comments. Post your answer, Bob! Get credit for it. 🙂

function start() {
    var myspan = document.getElementById("myspan");
    myspan.onclick = function() { alert ("hi"); };

    var mydiv = document.getElementById("mydiv");
    var newcontent = document.createElement('div');
    newcontent.innerHTML = "bar";

    while (newcontent.firstChild) {
        mydiv.appendChild(newcontent.firstChild);
    }
}

Second answer

Now, it is 2012, and jQuery has append and prepend functions that do exactly this, add content without effecting current content. Very useful.

Third answer

As a slight (but related) asside, if you use a javascript library such as jquery (v1.3) to do your dom manipulation you can make use of live events whereby you set up a handler like:

 $("#myspan").live("click", function(){
  alert('hi');
});

and it will be applied to that selector at all times during any kind of jquery manipulation. For live events see: docs.jquery.com/events/live for jquery manipulation see: docs.jquery.com/manipulation

Reprint:https://stackoverflow.com/questions/595808/is-it-possible-to-append-to-innerhtml-without-destroying-descendants-event-list
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