Develop Reference

How can i add user to database using a combination of Javascript and PHP [duplicate]

Is there a way I can run a php function through a JS function?
something like this:
<script type="text/javascript">
function test(){
document.getElementById("php_code").innerHTML="<?php
query("hello"); ?>";
}
</script>
<a href="#" style="display:block; color:#000033; font-family:Tahoma; font-size:12px;"
onclick="test(); return false;"> test </a>
<span id="php_code"> </span>
I basically want to run the php function query("hello"), when I click on the href called "Test" which would call the php function.

This is, in essence, what AJAX is for. Your page loads, and you add an event to an element. When the user causes the event to be triggered, say by clicking something, your Javascript uses the XMLHttpRequest object to send a request to a server.
After the server responds (presumably with output), another Javascript function/event gives you a place to work with that output, including simply sticking it into the page like any other piece of HTML.
You can do it "by hand" with plain Javascript , or you can use jQuery. Depending on the size of your project and particular situation, it may be more simple to just use plain Javascript .
Plain Javascript
In this very basic example, we send a request to myAjax.php when the user clicks a link. The server will generate some content, in this case "hello world!". We will put into the HTML element with the id output.
The javascript
// handles the click event for link 1, sends the query
function getOutput() {
getRequest(
'myAjax.php', // URL for the PHP file
drawOutput, // handle successful request
drawError // handle error
);
return false;
}
// handles drawing an error message
function drawError() {
var container = document.getElementById('output');
container.innerHTML = 'Bummer: there was an error!';
}
// handles the response, adds the html
function drawOutput(responseText) {
var container = document.getElementById('output');
container.innerHTML = responseText;
}
// helper function for cross-browser request object
function getRequest(url, success, error) {
var req = false;
try{
// most browsers
req = new XMLHttpRequest();
} catch (e){
// IE
try{
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch(e) {
// try an older version
try{
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch(e) {
return false;
}
}
}
if (!req) return false;
if (typeof success != 'function') success = function () {};
if (typeof error!= 'function') error = function () {};
req.onreadystatechange = function(){
if(req.readyState == 4) {
return req.status === 200 ?
success(req.responseText) : error(req.status);
}
}
req.open("GET", url, true);
req.send(null);
return req;
}
The HTML
test
<div id="output">waiting for action</div>
The PHP
// file myAjax.php
<?php
echo 'hello world!';
?>
Try it out: http://jsfiddle.net/GRMule/m8CTk/
With a javascript library (jQuery et al)
Arguably, that is a lot of Javascript code. You can shorten that up by tightening the blocks or using more terse logic operators, of course, but there's still a lot going on there. If you plan on doing a lot of this type of thing on your project, you might be better off with a javascript library.
Using the same HTML and PHP from above, this is your entire script (with jQuery included on the page). I've tightened up the code a little to be more consistent with jQuery's general style, but you get the idea:
// handles the click event, sends the query
function getOutput() {
$.ajax({
url:'myAjax.php',
complete: function (response) {
$('#output').html(response.responseText);
},
error: function () {
$('#output').html('Bummer: there was an error!');
}
});
return false;
}
Try it out: http://jsfiddle.net/GRMule/WQXXT/
Don't rush out for jQuery just yet: adding any library is still adding hundreds or thousands of lines of code to your project just as surely as if you had written them. Inside the jQuery library file, you'll find similar code to that in the first example, plus a whole lot more. That may be a good thing, it may not. Plan, and consider your project's current size and future possibility for expansion and the target environment or platform.
If this is all you need to do, write the plain javascript once and you're done.
Documentation
AJAX on MDN - https://developer.mozilla.org/en/ajax
XMLHttpRequest on MDN - https://developer.mozilla.org/en/XMLHttpRequest
XMLHttpRequest on MSDN - http://msdn.microsoft.com/en-us/library/ie/ms535874%28v=vs.85%29.aspx
jQuery - http://jquery.com/download/
jQuery.ajax - http://api.jquery.com/jQuery.ajax/

PHP is evaluated at the server; javascript is evaluated at the client/browser, thus you can't call a PHP function from javascript directly. But you can issue an HTTP request to the server that will activate a PHP function, with AJAX.

The only way to execute PHP from JS is AJAX.
You can send data to server (for eg, GET /ajax.php?do=someFunction)
then in ajax.php you write:
function someFunction() {
echo 'Answer';
}
if ($_GET['do'] === "someFunction") {
someFunction();
}
and then, catch the answer with JS (i'm using jQuery for making AJAX requests)
Probably you'll need some format of answer. See JSON or XML, but JSON is easy to use with JavaScript. In PHP you can use function json_encode($array); which gets array as argument.

I recently published a jQuery plugin which allows you to make PHP function calls in various ways: https://github.com/Xaxis/jquery.php
Simple example usage:
// Both .end() and .data() return data to variables
var strLenA = P.strlen('some string').end();
var strLenB = P.strlen('another string').end();
var totalStrLen = strLenA + strLenB;
console.log( totalStrLen ); // 25
// .data Returns data in an array
var data1 = P.crypt("Some Crypt String").data();
console.log( data1 ); // ["$1$Tk1b01rk$shTKSqDslatUSRV3WdlnI/"]

I have a way to make a Javascript call to a PHP function written on the page (client-side script). The PHP part 'to be executed' only occurs on the server-side on load or refreshing'. You avoid 'some' server-side resources. So, manipulating the DOM:
<?PHP
echo "You have executed the PHP function 'after loading o refreshing the page<br>";
echo "<i><br>The server programmatically, after accessing the command line resources on the server-side, copied the 'Old Content' from the 'text.txt' file and then changed 'Old Content' to 'New Content'. Finally sent the data to the browser.<br><br>But If you execute the PHP function n times your page always displays 'Old Content' n times, even though the file content is always 'New Content', which is demonstrated (proof 1) by running the 'cat texto.txt' command in your shell. Displaying this text on the client side proves (proof 2) that the browser executed the PHP function 'overflying' the PHP server-side instructions, and this is because the browser engine has restricted, unobtrusively, the execution of scripts on the client-side command line.<br><br>So, the server responds only by loading or refreshing the page, and after an Ajax call function or a PHP call via an HTML form. The rest happens on the client-side, presumably through some form of 'RAM-caching</i>'.<br><br>";
function myPhp(){
echo"The page says: Hello world!<br>";
echo "The page says that the Server '<b>said</b>': <br>1. ";
echo exec('echo $(cat texto.txt);echo "Hello world! (New content)" > texto.txt');echo "<br>";
echo "2. I have changed 'Old content' to '";
echo exec('echo $(cat texto.txt)');echo ".<br><br>";
echo "Proofs 1 and 2 say that if you want to make a new request to the server, you can do: 1. reload the page, 2. refresh the page, 3. make a call through an HTML form and PHP code, or 4. do a call through Ajax.<br><br>";
}
?>
<div id="mainx"></div>
<script>
function callPhp(){
var tagDiv1 = document.createElement("div");
tagDiv1.id = 'contentx';
tagDiv1.innerHTML = "<?php myPhp(); ?>";
document.getElementById("mainx").appendChild(tagDiv1);
}
</script>
<input type="button" value="CallPHP" onclick="callPhp()">
Note: The texto.txt file has the content 'Hello world! (Old content).
The 'fact' is that whenever I click the 'CallPhp' button I get the message 'Hello world!' printed on my page. Therefore, a server-side script is not always required to execute a PHP function via Javascript.
But the execution of the bash commands only happens while the page is loading or refreshing, never because of that kind of Javascript apparent-call raised before. Once the page is loaded, the execution of bash scripts requires a true-call (PHP, Ajax) to a server-side PHP resource.
So, If you don't want the user to know what commands are running on the server:
You 'should' use the execution of the commands indirectly through a PHP script on the server-side (PHP-form, or Ajax on the client-side).
Otherwise:
If the output of commands on the server-side is not delayed:
You 'can' use the execution of the commands directly from the page (less 'cognitive' resources—less PHP and more Bash—and less code, less time, usually easier, and more comfortable if you know the bash language).
Otherwise:
You 'must' use Ajax.

How can i use php function in script tag? [duplicate]

Is there a way I can run a php function through a JS function?
something like this:
<script type="text/javascript">
function test(){
document.getElementById("php_code").innerHTML="<?php
query("hello"); ?>";
}
</script>
<a href="#" style="display:block; color:#000033; font-family:Tahoma; font-size:12px;"
onclick="test(); return false;"> test </a>
<span id="php_code"> </span>
I basically want to run the php function query("hello"), when I click on the href called "Test" which would call the php function.

This is, in essence, what AJAX is for. Your page loads, and you add an event to an element. When the user causes the event to be triggered, say by clicking something, your Javascript uses the XMLHttpRequest object to send a request to a server.
After the server responds (presumably with output), another Javascript function/event gives you a place to work with that output, including simply sticking it into the page like any other piece of HTML.
You can do it "by hand" with plain Javascript , or you can use jQuery. Depending on the size of your project and particular situation, it may be more simple to just use plain Javascript .
Plain Javascript
In this very basic example, we send a request to myAjax.php when the user clicks a link. The server will generate some content, in this case "hello world!". We will put into the HTML element with the id output.
The javascript
// handles the click event for link 1, sends the query
function getOutput() {
getRequest(
'myAjax.php', // URL for the PHP file
drawOutput, // handle successful request
drawError // handle error
);
return false;
}
// handles drawing an error message
function drawError() {
var container = document.getElementById('output');
container.innerHTML = 'Bummer: there was an error!';
}
// handles the response, adds the html
function drawOutput(responseText) {
var container = document.getElementById('output');
container.innerHTML = responseText;
}
// helper function for cross-browser request object
function getRequest(url, success, error) {
var req = false;
try{
// most browsers
req = new XMLHttpRequest();
} catch (e){
// IE
try{
req = new ActiveXObject("Msxml2.XMLHTTP");
} catch(e) {
// try an older version
try{
req = new ActiveXObject("Microsoft.XMLHTTP");
} catch(e) {
return false;
}
}
}
if (!req) return false;
if (typeof success != 'function') success = function () {};
if (typeof error!= 'function') error = function () {};
req.onreadystatechange = function(){
if(req.readyState == 4) {
return req.status === 200 ?
success(req.responseText) : error(req.status);
}
}
req.open("GET", url, true);
req.send(null);
return req;
}
The HTML
test
<div id="output">waiting for action</div>
The PHP
// file myAjax.php
<?php
echo 'hello world!';
?>
Try it out: http://jsfiddle.net/GRMule/m8CTk/
With a javascript library (jQuery et al)
Arguably, that is a lot of Javascript code. You can shorten that up by tightening the blocks or using more terse logic operators, of course, but there's still a lot going on there. If you plan on doing a lot of this type of thing on your project, you might be better off with a javascript library.
Using the same HTML and PHP from above, this is your entire script (with jQuery included on the page). I've tightened up the code a little to be more consistent with jQuery's general style, but you get the idea:
// handles the click event, sends the query
function getOutput() {
$.ajax({
url:'myAjax.php',
complete: function (response) {
$('#output').html(response.responseText);
},
error: function () {
$('#output').html('Bummer: there was an error!');
}
});
return false;
}
Try it out: http://jsfiddle.net/GRMule/WQXXT/
Don't rush out for jQuery just yet: adding any library is still adding hundreds or thousands of lines of code to your project just as surely as if you had written them. Inside the jQuery library file, you'll find similar code to that in the first example, plus a whole lot more. That may be a good thing, it may not. Plan, and consider your project's current size and future possibility for expansion and the target environment or platform.
If this is all you need to do, write the plain javascript once and you're done.
Documentation
AJAX on MDN - https://developer.mozilla.org/en/ajax
XMLHttpRequest on MDN - https://developer.mozilla.org/en/XMLHttpRequest
XMLHttpRequest on MSDN - http://msdn.microsoft.com/en-us/library/ie/ms535874%28v=vs.85%29.aspx
jQuery - http://jquery.com/download/
jQuery.ajax - http://api.jquery.com/jQuery.ajax/

PHP is evaluated at the server; javascript is evaluated at the client/browser, thus you can't call a PHP function from javascript directly. But you can issue an HTTP request to the server that will activate a PHP function, with AJAX.

The only way to execute PHP from JS is AJAX.
You can send data to server (for eg, GET /ajax.php?do=someFunction)
then in ajax.php you write:
function someFunction() {
echo 'Answer';
}
if ($_GET['do'] === "someFunction") {
someFunction();
}
and then, catch the answer with JS (i'm using jQuery for making AJAX requests)
Probably you'll need some format of answer. See JSON or XML, but JSON is easy to use with JavaScript. In PHP you can use function json_encode($array); which gets array as argument.

I recently published a jQuery plugin which allows you to make PHP function calls in various ways: https://github.com/Xaxis/jquery.php
Simple example usage:
// Both .end() and .data() return data to variables
var strLenA = P.strlen('some string').end();
var strLenB = P.strlen('another string').end();
var totalStrLen = strLenA + strLenB;
console.log( totalStrLen ); // 25
// .data Returns data in an array
var data1 = P.crypt("Some Crypt String").data();
console.log( data1 ); // ["$1$Tk1b01rk$shTKSqDslatUSRV3WdlnI/"]

I have a way to make a Javascript call to a PHP function written on the page (client-side script). The PHP part 'to be executed' only occurs on the server-side on load or refreshing'. You avoid 'some' server-side resources. So, manipulating the DOM:
<?PHP
echo "You have executed the PHP function 'after loading o refreshing the page<br>";
echo "<i><br>The server programmatically, after accessing the command line resources on the server-side, copied the 'Old Content' from the 'text.txt' file and then changed 'Old Content' to 'New Content'. Finally sent the data to the browser.<br><br>But If you execute the PHP function n times your page always displays 'Old Content' n times, even though the file content is always 'New Content', which is demonstrated (proof 1) by running the 'cat texto.txt' command in your shell. Displaying this text on the client side proves (proof 2) that the browser executed the PHP function 'overflying' the PHP server-side instructions, and this is because the browser engine has restricted, unobtrusively, the execution of scripts on the client-side command line.<br><br>So, the server responds only by loading or refreshing the page, and after an Ajax call function or a PHP call via an HTML form. The rest happens on the client-side, presumably through some form of 'RAM-caching</i>'.<br><br>";
function myPhp(){
echo"The page says: Hello world!<br>";
echo "The page says that the Server '<b>said</b>': <br>1. ";
echo exec('echo $(cat texto.txt);echo "Hello world! (New content)" > texto.txt');echo "<br>";
echo "2. I have changed 'Old content' to '";
echo exec('echo $(cat texto.txt)');echo ".<br><br>";
echo "Proofs 1 and 2 say that if you want to make a new request to the server, you can do: 1. reload the page, 2. refresh the page, 3. make a call through an HTML form and PHP code, or 4. do a call through Ajax.<br><br>";
}
?>
<div id="mainx"></div>
<script>
function callPhp(){
var tagDiv1 = document.createElement("div");
tagDiv1.id = 'contentx';
tagDiv1.innerHTML = "<?php myPhp(); ?>";
document.getElementById("mainx").appendChild(tagDiv1);
}
</script>
<input type="button" value="CallPHP" onclick="callPhp()">
Note: The texto.txt file has the content 'Hello world! (Old content).
The 'fact' is that whenever I click the 'CallPhp' button I get the message 'Hello world!' printed on my page. Therefore, a server-side script is not always required to execute a PHP function via Javascript.
But the execution of the bash commands only happens while the page is loading or refreshing, never because of that kind of Javascript apparent-call raised before. Once the page is loaded, the execution of bash scripts requires a true-call (PHP, Ajax) to a server-side PHP resource.
So, If you don't want the user to know what commands are running on the server:
You 'should' use the execution of the commands indirectly through a PHP script on the server-side (PHP-form, or Ajax on the client-side).
Otherwise:
If the output of commands on the server-side is not delayed:
You 'can' use the execution of the commands directly from the page (less 'cognitive' resources—less PHP and more Bash—and less code, less time, usually easier, and more comfortable if you know the bash language).
Otherwise:
You 'must' use Ajax.

How to make JS wait until protocol execution finished

I have a custom URL protocol handler cgit:[...]
It launches up a background process which configures some stuff on the local machine. The protocol works fine, i'm launching it from JavaScript (currently using document.location = 'cgit:[...]'), but i actually want JavaScript to wait until the associated program exits.
So basically the steps i want JavaScript to do:
JavaScript does something
JavaScript launches cgit:[...]
Javascript waits until cgit:[...] exits
JavaScript does something else
Code:
function launchCgit(params)
{
showProgressBar();
document.location="cgit:"+params;
document.addEventListener( /* CGit-Program exited event */, hideProgressBar );
}
or:
function launchCgit(params)
{
showProgressBar();
// setLocationAndWait("cgit:"+params);
hideProgressBar();
}
Any ideas if this is possible?

Since this isn't really an expected use of window.location I would doubt that there's an easy way. My recommendation would be to use an AJAX request and have the c++ program send a response when it's done. That way, whatever code needs to run after the c++ program can be run when the request completes.

As i didn't find a suitable way to solve my problem using ajax requests or anything similar, i finally solved my problem using a kind-of-ugly workarround including XmlHttpRequest
For launching the protocol i'm still using document.location=cgit:[...]
I'm using a server side system including "lock-files" - that's like generic dummy files, with generated names for each request.
Once the user requests to open the custom protocol, such a file is being generated on the server specifically for that one protocol-opening-request.
I created a folder called "$locks" on the server where these files are being placed in. Once the protocol-associated program exits, the appropriate file is being deleted.
The website continuously checks if the file for a request still exists using XmlHttpRequest and fires a callback if it doesn't (example timout between tests: 1 sec).
The structure of the new files is the following:
lockThisRequest.php: It creates a file in the $locks directory based on the req url-parameter.
unlockThisRequest.php: It deletes a file in the $locks directory; again based on the req url-parameter.
The JavaScript part of it goes:
function launchCgit(params,callback)
{
var lock = /* Generate valid filename from params variable */;
// "Lock" that Request (means: telling the server that a request with this ID is now in use)
var locker = new XmlHttpRequest();
locker.open('GET', 'lockThisRequest.php?req='+lock, true)
locker.send(null);
function retry()
{
// Test if the lock-file still exists on the server
var req = new XmlHttpRequest();
req.open('GET', '$locks/'+lock, true);
req.onReadyStateChanged=function()
{
if (req.readyState == 4)
{
if (req.status == 200)
{
// lock-file exists -> cgit has not exited yet
window.setTimeout(retry,1000);
}
else if (req.status == 404)
{
// lock-file not found -> request has been proceeded
callback();
}
}
}
req.send(null);
}
document.location = 'cgit:'+params; // execute custom protocol
retry(); // initialize lockfileCheck-loop
}
Ussage is:
launchCgit("doThisAndThat",function()
{
alert("ThisAndThat finished.");
});
the lockThisRequest.php-file:
<?php
file_put_contents("$locks/".$_GET["req"],""); // Create lock file
?>
and unlockThisRequest.php:
<?php
unlink("../\$locks/".$_GET["req"]); // Delete lock file
?>
The local program / script executed by the protocol can simply call something like:
#!/bin/bash
curl "http://servername/unlockThisRequest.php?req=$1"
after it finished.
As i just said this works, but it's anything else than nice (congratulations if you kept track of those instructions)
I'd rather prefered a more simple way and (important) this also may cause security issues with the lockThisRequest.php and unlockThisRequest.php files!
I'm fine with this solution, because i'm only using it on a password protected private page. But if you plan to use it on a public or non protected page, you may want to add some security to the php files.
Anyways, the solution works for me now, but if anyone finds a better way to do it - for example by using ajax requests - he/she would be very welcome to add that way to the respective stackoverflow-documentation or the like and post a link to it on this thread. I'd still be interested in alternative solutions :)

Calling php function inside Javascript code

I know that this question has been asked before but all of them are using jQuery library and i would like to use Javascript only, no libraries so please bear with me.
This link shows the PHP function being called from jQuery.
How can I call PHP functions by JavaScript?
The code is calling a function that displays images.
I have the following code and I don't understand how to call the function from the mainfile.php and not functions.php.
mainfile.php
<button id="btn">Click</btn> // button that calls ajax file
<div id="div"></div> // div where it should appear
<script>
function loadXML(method, url, div, index)
{
var xmlhttp;
try
{
xmlhttp = new XMLHttpRequest();
}
catch(e)
{
try
{
xmlhttp = new ActiveXObject('Microsoft.XMLHTTP');
}
catch(e)
{
alert('sorry');
}
}
xmlhttp.onreadystatechange = function()
{
if( xmlhttp.readyState === 4 && xmlhttp.status === 200 )
{
if( index === null || index === 'undefined' || xmlhttp === '')
{
document.getElementById(div).innerHTML = xmlhttp.responseText;
}
}
};
xmlhttp.open(method, url, true);
xmlhttp.send(null);
}
document.getElementById('btn').addEventListener('click', function()
{
loadXML('GET', 'imgs.php', 'div', null);
}, false);
</script>
functions.php
<?php
function getImgs($dir, $type)
{
$images = glob($dir . $type);
print_r($images); // for now i'm printing the array the way it is to see the function work
}
getImgs('images/', '.*JPG'); // calling function from php file works
?>
I would like to call the function from inside mainfile.php without using any jQuery library, only plain Javascript, it should be possible considering that the libraries are made with Javascript. I don't know where to call the function from inside mainfile.php. Any help would be appreciated.
The reason I am getting files from php is because it is easier to load them into the DOM, I need to make an image gallery so I would like to know if it will be possible to manipulate the images when they are loaded into the DOM using AJAX.

You can only do it by Making an AJAX request to a php page while passing in a parameter to initialise the function.
That means your AJAX will send in for example "functionName" to the php page "functionsListPage.php"
The GET will be recieved :
if (isset($_GET['functionName']))
functionExec();
This is the only way so you are not calling direct from the client however you are indicating to the server you want to run a predefined request.
You cannot call a PHP function directly from the clientside.

It's just like the answer from #Pogrindis, but i think so explanation is needed
It is possible to do it with with plain JavaScript with a little workaround!
What you need to do is the following in JavaScript after the xmlhttp.open();
var functionname = getImgs;
xmlhttp.open();
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded")
xmlhttp.send(functionname);
What this does is simple: it sends the data to the server, so you php file can get this parameter!
In your called php file you need something like this:
if( isset($_POST['functionname']) )
{
if($_POST['functionname']) == 'getImgs'
{
getImgs();
}
}
Of course you need to make sure that you post the data with post in this case, if you want to use get you need to change the php to $_GET
Notice: This is totally unsafe right now! No escaping from the coming data and anything else.

Calling a JavaScript function returned from an Ajax response

I have a system where I send an Ajax command, which returns a script block with a function in it. After this data is correctly inserted in the DIV, I want to be able to call this function to perform the required actions.
Is this possible?

I think to correctly interpret your question under this form: "OK, I'm already done with all the Ajax stuff; I just wish to know if the JavaScript function my Ajax callback inserted into the DIV is callable at any time from that moment on, that is, I do not want to call it contextually to the callback return".
OK, if you mean something like this the answer is yes, you can invoke your new code by that moment at any time during the page persistence within the browser, under the following conditions:
1) Your JavaScript code returned by Ajax callback must be syntactically OK;
2) Even if your function declaration is inserted into a <script> block within an existing <div> element, the browser won't know the new function exists, as the declaration code has never been executed. So, you must eval() your declaration code returned by the Ajax callback, in order to effectively declare your new function and have it available during the whole page lifetime.
Even if quite dummy, this code explains the idea:
<html>
<body>
<div id="div1">
</div>
<div id="div2">
<input type="button" value="Go!" onclick="go()" />
</div>
<script type="text/javascript">
var newsc = '<script id="sc1" type="text/javascript">function go() { alert("GO!") }<\/script>';
var e = document.getElementById('div1');
e.innerHTML = newsc;
eval(document.getElementById('sc1').innerHTML);
</script>
</body>
</html>
I didn't use Ajax, but the concept is the same (even if the example I chose sure isn't much smart :-)
Generally speaking, I do not question your solution design, i.e. whether it is more or less appropriate to externalize + generalize the function in a separate .js file and the like, but please take note that such a solution could raise further problems, especially if your Ajax invocations should repeat, i.e. if the context of the same function should change or in case the declared function persistence should be concerned, so maybe you should seriously consider to change your design to one of the suggested examples in this thread.
Finally, if I misunderstood your question, and you're talking about contextual invocation of the function when your Ajax callback returns, then my feeling is to suggest the Prototype approach described by krosenvold, as it is cross-browser, tested and fully functional, and this can give you a better roadmap for future implementations.

Note: eval() can be easily misused, let say that the request is intercepted by a third party and sends you not trusted code. Then with eval() you would be running this not trusted code. Refer here for the dangers of eval().
Inside the returned HTML/Ajax/JavaScript file, you will have a JavaScript tag. Give it an ID, like runscript. It's uncommon to add an id to these tags, but it's needed to reference it specifically.
<script type="text/javascript" id="runscript">
alert("running from main");
</script>
In the main window, then call the eval function by evaluating only that NEW block of JavaScript code (in this case, it's called runscript):
eval(document.getElementById("runscript").innerHTML);
And it works, at least in Internet Explorer 9 and Google Chrome.

It is fully possible, and there are even some fairly legitimate use cases for this. Using the Prototype framework it's done as follows.
new Ajax.Updater('items', '/items.url', {
parameters: { evalJS: true}
});
See documentation of the Ajax updater. The options are in the common options set. As usual, there are some caveats about where "this" points to, so read the fine print.
The JavaScript code will be evaluated upon load. If the content contains function myFunc(),
you could really just say myFunc() afterwards. Maybe as follows.
if (window["myFunc"])
myFunc()
This checks if the function exists. Maybe someone has a better cross-browser way of doing that which works in Internet Explorer 6.

That seems a rather weird design for your code - it generally makes more sense to have your functions called directly from a .js file, and then only retrieve data with the Ajax call.
However, I believe it should work by calling eval() on the response - provided it is syntactically correct JavaScript code.

With jQuery I would do it using getScript

Just remember if you create a function the way below through ajax...
function foo()
{
console.log('foo');
}
...and execute it via eval, you'll probably get a context problem.
Take this as your callback function:
function callback(result)
{
responseDiv = document.getElementById('responseDiv');
responseDiv.innerHTML = result;
scripts = responseDiv.getElementsByTagName('script');
eval(scripts[0]);
}
You'll be declaring a function inside a function, so this new function will be accessible only on that scope.
If you want to create a global function in this scenario, you could declare it this way:
window.foo = function ()
{
console.log('foo');
};
But, I also think you shouldn't be doing this...
Sorry for any mistake here...

I would like to add that there's an eval function in jQuery allowing you to eval the code globally which should get you rid of any contextual problems. The function is called globalEval() and it worked great for my purposes. Its documentation can be found here.
This is the example code provided by the jQuery API documentation:
function test()
{
jQuery.globalEval("var newVar = true;")
}
test();
// newVar === true
This function is extremely useful when it comes to loading external scripts dynamically which you apparently were trying to do.

A checklist for doing such a thing:
the returned Ajax response is eval(ed).
the functions are declared in form func_name = function() {...}
Better still, use frameworks which handles it like in Prototype. You have Ajax.updater.

PHP side code
Name of file class.sendCode.php
<?php
class sendCode{
function __construct($dateini,$datefin) {
echo $this->printCode($dateini,$datefin);
}
function printCode($dateini,$datefin){
$code =" alert ('code Coming from AJAX {$this->dateini} and {$this->datefin}');";
//Insert all the code you want to execute,
//only javascript or Jquery code , dont incluce <script> tags
return $code ;
}
}
new sendCode($_POST['dateini'],$_POST['datefin']);
Now from your Html page you must trigger the ajax function to send the data.
.... <script src="http://code.jquery.com/jquery-1.9.1.js"></script> ....
Date begin: <input type="text" id="startdate"><br>
Date end : <input type="text" id="enddate"><br>
<input type="button" value="validate'" onclick="triggerAjax()"/>
Now at our local script.js we will define the ajax
function triggerAjax() {
$.ajax({
type: "POST",
url: 'class.sendCode.php',
dataType: "HTML",
data : {
dateini : $('#startdate').val(),
datefin : $('#enddate').val()},
success: function(data){
$.globalEval(data);
// here is where the magic is made by executing the data that comes from
// the php class. That is our javascript code to be executed
}
});
}

This code work as well, instead eval the html i'm going to append the script to the head
function RunJS(objID) {
//alert(http_request.responseText);
var c="";
var ob = document.getElementById(objID).getElementsByTagName("script");
for (var i=0; i < ob.length - 1; i++) {
if (ob[i + 1].text != null)
c+=ob[i + 1].text;
}
var s = document.createElement("script");
s.type = "text/javascript";
s.text = c;
document.getElementsByTagName("head")[0].appendChild(s);
}

My usual ajax calling function:
function xhr_new(targetId, url, busyMsg, finishCB)
{
var xhr;
if(busyMsg !== undefined)
document.getElementById(targetId).innerHTML = busyMsg;
try { xhr = new ActiveXObject('Msxml2.XMLHTTP'); }
catch(e)
{
try { xhr = new ActiveXObject('Microsoft.XMLHTTP'); }
catch(e2)
{
try { xhr = new XMLHttpRequest(); }
catch(e3) { xhr = false; }
}
}
xhr.onreadystatechange = function()
{
if(xhr.readyState == 4)
{
if(xhr.status == 200)
{
var target = document.getElementById(targetId)
target.innerHTML = xhr.responseText;
var scriptElements = target.getElementsByTagName("script");
var i;
for(i = 0; i < scriptElements.length; i++)
eval(scriptElements[i].innerHTML);
if(finishCB !== undefined)
finishCB();
}
else
document.getElementById(targetId).innerHTML = 'Error code: ' + xhr.status;
}
};
xhr.open('GET', url, true);
xhr.send(null);
// return xhr;
}
Some explanation:
targetId is an (usually div) element ID where the ajax call result text will goes.
url is the ajax call url.
busyMsg will be the temporary text in the target element.
finishCB will be called when the ajax transaction finished successfully.
As you see in the xhr.onreadystatechange = function() {...} all of the <script> elements will be collected from the ajax response and will be run one by one. It appears to work very well for me. The two last parameter is optional.

I've tested this and it works. What's the problem? Just put the new function inside your javascript element and then call it. It will work.

This does not sound like a good idea.
You should abstract out the function to include in the rest of your JavaScript code from the data returned by Ajax methods.
For what it's worth, though, (and I don't understand why you're inserting a script block in a div?) even inline script methods written in a script block will be accessible.

I tried all the techniques offered here but finally the way that worked was simply to put the JavaScript function inside the page / file where it is supposed to happen and call it from the response part of the Ajax simply as a function:
...
}, function(data) {
afterOrder();
}
This Worked on the first attempt, so I decided to share.

I solved this today by putting my JavaScript at the bottom of the response HTML.
I had an AJAX request that returned a bunch of HTML that was displayed in an overlay. I needed to attach a click event to a button in the returned response HTML/overlay. On a normal page, I would wrap my JavaScript in a "window.onload" or "$(document).ready" so that it would attach the event handler to the DOM object after the DOM for the new overlay had been rendered, but because this was an AJAX response and not a new page load, that event never happened, the browser never executed my JavaScript, my event handler never got attached to the DOM element, and my new piece of functionality didn't work. Again, I solved my "executing JavaScript in an AJAX response problem" by not using "$(document).ready" in the head of the document, but by placing my JavaScript at the end of the document and having it run after the HTML/DOM had been rendered.

If your AJAX script takes more than a couple milliseconds to run, eval() will always run ahead and evaluate the empty response element before AJAX populates it with the script you're trying to execute.
Rather than mucking around with timing and eval(), here is a pretty simple workaround that should work in most situations and is probably a bit more secure. Using eval() is generally frowned upon because the characters being evaluated as code can easily be manipulated client-side.
Concept
Include your javascript function in the main page. Write it so that any dynamic elements can be accepted as arguments.
In your AJAX file, call the function by using an official DOM event (onclick, onfocus, onblur, onload, etc.) Depending on what other elements are in your response, you can get pretty clever about making it feel seamless. Pass your dynamic elements in as arguments.
When your response element gets populated and the event takes place, the function runs.
Example
In this example, I want to attach a dynamic autocomplete list from the jquery-ui library to an AJAX element AFTER the element has been added to the page. Easy, right?
start.php
<!DOCTYPE html>
<html>
<head>
<title>Demo</title>
<!-- these libraries are for the autocomplete() function -->
<link rel="stylesheet" type="text/css" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/themes/ui-lightness/jquery-ui.css">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.11.4/jquery-ui.min.js"></script>
<script type="text/javascript">
<!--
// this is the ajax call
function editDemoText(ElementID,initialValue) {
try { ajaxRequest = new XMLHttpRequest();
} catch (e) {
try { ajaxRequest = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
try { ajaxRequest = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
return false;
}}}
ajaxRequest.onreadystatechange = function() {
if ( ajaxRequest.readyState == 4 ) {
var ajaxDisplay = document.getElementById('responseDiv');
ajaxDisplay.innerHTML = ajaxRequest.responseText;
}
}
var queryString = "?ElementID="+ElementID+"&initialValue="+initialValue;
ajaxRequest.open("GET", "ajaxRequest.php"+queryString, true);
ajaxRequest.send(null);
}
// this is the function we wanted to call in AJAX,
// but we put it here instead with an argument (ElementID)
function AttachAutocomplete(ElementID) {
// this list is static, but can easily be pulled in from
// a database using PHP. That would look something like this:
/*
* $list = "";
* $r = mysqli_query($mysqli_link, "SELECT element FROM table");
* while ( $row = mysqli_fetch_array($r) ) {
* $list .= "\".str_replace('"','\"',$row['element'])."\",";
* }
* $list = rtrim($list,",");
*/
var availableIDs = ["Demo1","Demo2","Demo3","Demo4"];
$("#"+ElementID).autocomplete({ source: availableIDs });
}
//-->
</script>
</head>
<body>
<!-- this is where the AJAX response sneaks in after DOM is loaded -->
<!-- we're using an onclick event to trigger the initial AJAX call -->
<div id="responseDiv">I am editable!</div>
</body>
</html>
ajaxRequest.php
<?php
// for this application, onfocus works well because we wouldn't really
// need the autocomplete populated until the user begins typing
echo "<input type=\"text\" id=\"".$_GET['ElementID']."\" onfocus=\"AttachAutocomplete('".$_GET['ElementID']."');\" value=\"".$_GET['initialValue']."\" />\n";
?>

I needed to get something to do this, I find that this has worked for a long time for me, just posting this here as one of many solutions, I like to have solutions without jQuery and the following function may help you, you can pass the full html with script tags in and it will parse and execute.
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 {
if (scripts[i] != '')
{
try { //IE
execScript(scripts[i]);
}
catch(ex) //Firefox
{
window.eval(scripts[i]);
}
}
}
catch(e) {
// do what you want here when a script fails
if (e instanceof SyntaxError) console.log (e.message+' - '+scripts[i]);
}
}
// Return the cleaned source
return source;
}

Federico Zancan's answer is correct but you don't have to give your script an ID and eval all your script. Just eval your function name and it can be called.
To achieve this in our project, we wrote a proxy function to call the function returned inside the Ajax response.
function FunctionProxy(functionName){
var func = eval(functionName);
func();
}