Executing javascript script after ajax-loaded a page - doesn't work - php

Question

I'm trying to get a page with AJAX, but when I get that page and it includes Javascript code - it doesn't execute it.
Why?
Simple code in my ajax page:
<script type="text/javascript">
alert("Hello");
</script>
...and it doesn't execute it. I'm trying to use Google Maps API and add markers with AJAX, so whenever I add one I execute a AJAX page that gets the new marker, stores it in a database and should add the marker "dynamically" to the map.
But since I can't execute a single javascript function this way, what do I do?
Is my functions that I've defined on the page beforehand protected or private?
** UPDATED WITH AJAX FUNCTION **
function ajaxExecute(id, link, query)
{
if (query != null)
{
query = query.replace("amp;", "");
}
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)
{
if (id != null)
{
document.getElementById(id).innerHTML=xmlhttp.responseText;
}
}
}
if (query == null)
{
xmlhttp.open("GET",link,true);
}
else
{
if (query.substr(0, 1) != "?")
{
xmlhttp.open("GET",link+"?"+query,true);
}
else
{
xmlhttp.open("GET",link+query,true);
}
}
xmlhttp.send();
}
** Solution by Deukalion **
var content = xmlhttp.responseText;
if (id != null)
{
document.getElementById(id).innerHTML=content;
var script = content.match("<script[^>]*>[^<]*</script>");
if (script != null)
{
script = script.toString().replace('<script type="text/javascript">', '');
script = script.replace('</script>', '');
eval(script);
}
}
and on certain events, I had to within the script addevent listeners instead of just making a "select onchange='executeFunctionNotIncludedInAjaxFile();'" I had to addEventListener("change", functionName, false) for this. In the script that is being evaluated.

Answer 1

When you update your page by doing something like setting a container's innerHTML to some updated content, the browser simply will not run the scripts in it. You can locate the <script> tags, get their innerHTML (IE may prefer innerTEXT), and then eval() the scripts yourself (which is pretty much what jQuery does, though it finds the scripts with a regex before updating the DOM).

Answer 2

Use this function:
function parseScript(_source) {
var source = _source;
var scripts = new Array();
// Strip out tags
while(source.indexOf("<script") > -1 || source.indexOf("</script") > -1) {
var s = source.indexOf("<script");
var s_e = source.indexOf(">", s);
var e = source.indexOf("</script", s);
var e_e = source.indexOf(">", e);
// Add to scripts array
scripts.push(source.substring(s_e+1, e));
// Strip from source
source = source.substring(0, s) + source.substring(e_e+1);
}
// Loop through every script collected and eval it
for(var i=0; i<scripts.length; i++) {
try {
eval(scripts[i]);
}
catch(ex) {
// do what you want here when a script fails
}
}
// Return the cleaned source
return source;
}
then do parseScript(xmlhttp.responseText); when you're replacing/adding content.

Answer 3

In case some other people stumble upon this old thread, there is one issue with the accepted answer by Deukalion, there is one issue that may have been overlooked: as written, the script only looks for the first script tag. If multiple script tags exist, all others are overlooked.
A few minor tweaks would resolve the issue. Change one line from:
var script = content.match("<script[^>]*>[^<]*</script>");
To:
var script = content.match(/<script[^>]*>[^<]*<\/script>/g);
And another from:
script = script.toString().replace('<script type="text/javascript">', '');
To:
script = script.join("").replace(/<script type="text\/javascript">/g, '');
Now it will gather all the <script> code and execute them in the order found on the page. Otherwise it was an excellent solution.

Answer 4

After the AJAX request, you can make an "on success" function which can take the returned html and do something with it. Then something will be executed.
If there was a code example, then I could provide a code solution to the situation. But using just standard xmlhttprequest, the following could be done:
xhr = new XMLHttpRequest();
xhr.open("GET","ajax_info.txt",true);
xhr.onreadystatechange=function()
{
if (xhr.readyState==4 && xhr.status==200)
{
document.getElementById("myDiv").innerHTML = xhr.responseText;
}
}
xhr.send();
​