javascript XMLHttpRequest open php file and execute more javascript

Question

I have a main page, call it Main.php. On this page, is a button that when clicked, sets a div's innerHTML (already on Main.php, called divResults) with the results from Results.php.

When Results.php is called, the returned HTML "These Are The Results" is properly received and set as the contents to divResults on Main.php. However, any javascript from Results.php is not executed. As an example, I attempt to do a simple window.alert. Here is example code:

Main.php link button to begin the action:

<img src="$MyImageSource" onclick="ExpandDropdownDiv()" />

Main.php javascript function ExpandDropdownDiv():

function ExpandDropdownDiv(){

    if (window.XMLHttpRequest)/* code for IE7+, Firefox, Chrome, Opera, Safari */
    {
        xmlhttp=new XMLHttpRequest();
    }
    else
    {/* code for IE6, IE5 */
        xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
    }
    xmlhttp.onreadystatechange=function()
    {
        if (xmlhttp.readyState==4)/* && xmlhttp.status==200) */
        {
            document.getElementById("divResults").innerHTML=xmlhttp.responseText;
        }
    }
    xmlhttp.open("GET","Results.php",true);
    xmlhttp.send();

}

Results.php code example:

<script type="text/javascript">
    alert("Success");
</script>
These Are The Results

------------------ Edit - Update ------------------

The simple alert, from Results.php is just an example. If I were able to get this to work, I believe I could solve the rest of my problem on my own. However, I noticed a few comments suggesting to just place the alert in Main.php's javascript after i set the div's innerHTML. So, let me explain what I truly want to do with the javascript, after the div is set.

Image 1, shows some normal "Select" html elements, that have been transformed using jquery and the dropdown-check-list extension (.js). When the user clicks the colorful down arrow at the bottom, the div expands, (image 2) and two more "Select" elements are generated within this other .php file... the html is returned, and placed in the div. Thus, i do not need to reload the entire page, and can place the new select dropdowns just beneath the existing ones.

The problem is, to "transform" these normal select elements, there is some javascript that needs to be executed against that HTML:

$(document).ready(function() {
     $(".MultiSelect").dropdownchecklist(  {firstItemChecksAll: true, maxDropHeight: 300 , searchTextbox: true, width: 100, textFormatFunction: function(options) {
        var selectedOptions = options.filter(":selected");
        var countOfSelected = selectedOptions.size();
        var size = options.size();
        switch(countOfSelected) {
        case 0: return "All";
        case 1: return selectedOptions.text();
/*      case size: return "All"; */
        default: return countOfSelected + " selected";
        }
    } 
    }
    ); 
}

So, somehow I need to be able to execute javascript against the HTML that is generated from this other .php file. And simply calling the above code, after my divs innerHTML is filled, only re-generates the already existing dropdowns, not the two new ones.

Example Images

Answer 1

Here is a good read on understanding what you are doing: Eval embed JavaScript Ajax: YUI style

Making your code work with using eval(); but its not recommend for various reasons:

Let's take your php and modify it like this:

<script type="text/javascript">
    function result() {
        alert("Success");
    }
</script>
These Are The Results

and This is the callback function from AJAX. result(); is not executed because it doesn't get evaluated, and thus does not exist. which is in your case

if (xmlhttp.readyState==4)/* && xmlhttp.status==200) */
        {
            document.getElementById("divResults").innerHTML=xmlhttp.responseText;
            result(); // this function is embedded in the responseText
                      // and doesn't get evaluated. I.e. it doesn't exist
}

in order for the browser to recognize the result(); you must do an eval(); on all the JavaScript statements with in the script tags that you injected into the div with id divResults:

if (xmlhttp.readyState==4)/* && xmlhttp.status==200) */
        {
            document.getElementById("divResults").innerHTML=xmlhttp.responseText;
            var myDiv = document.getElementById("divResults");
            var myscripz = myDiv.getElementsByTagName('script');
            for(var i=myscripz.length; i--;){
                   eval(myscripz[i].innerHTML);
            }
            result(); //alerts success
}

Easy Way:

The easiest way i would do it is basically remove the JavaScript from the php and display the content, and after callback just do the rest of the JavaScript within the callback function php:

 echo 'These Are The Results';

JavaScript:

xmlhttp.onreadystatechange=function()
{
    if (xmlhttp.readyState==4)/* && xmlhttp.status==200) */
    {
        document.getElementById("divResults").innerHTML=xmlhttp.responseText;
        alert('success'); // or whatever else JavaScript you need to do
    }
}