How to trigger php code, in Javascript if condition

Question

Ok , so what I'm trying to do is trigger PHP code, only when the if condition is true (in javascript) , I understand that php is server side, and javascript is client side. The include of the php code works perfect except 1 thing , it gets triggered on page load actually , not when the if condition happens. If you can help me how to do this will be rly appreciated. I want the php file to be included ONLY when the if condition is true

thanks in advance

here's the code am using :

<html>
    <script src="//cdnjs.cloudflare.com/ajax/libs/visibility.js/0.5/visibility.min.js"></script>
    <script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.0/jquery.min.js" type="text/javascript"></script>
<script>
var seconds=20;
var flag=false;


$(document).ready(function(){
if (!flag)
Visibility.every(1000, tick);



function tick()
{
      display();

        if (seconds>0)
        {
         seconds--;
        }
        else
        {
          if (!flag){
          document.getElementById('more').innerHTML +="<?php include_once('Code.php'); 
          ?>";
          document.getElementById('more').style.visibility='visible';
          flag=true;
          }
        }
}
function display()
{
   $("#timer").html(seconds);
}
});
</script>
<div id="TrafficHeader" style="height:100px; background-color:grey; padding:20px;">
<div id="timer"></div>
<div id="more" style="visibility: hidden;"><a href="http://www.double-it.com/Traffic/index.php">View Next Ad</a></div></div>
<iframe id="myframe" src="<?php echo ''.$URL;?>" height="100%" width="100%" frameborder="0">
</iframe>
</body>
</html>

If you understood that PHP executes server-side and Javascript executes client-side, then you would know a Javascript conditional can not affect whether or not PHP executes in the way you show above. Use AJAX. — Travesty3
– Travesty3, Commented Sep 24, 2012 at 14:31

nana · Accepted Answer · 2012-09-24 14:58:23Z

5

This is not possible, at least not the way you are going about it.
The reason is that the if condition is evaluated on the client machine long after the server finish evaluating your php script.

First server has to finish procesing your php script, then imagine it has to pack it and then send the whole package to the client, which then unpacks it and renders the html and evaluates the javascript in html, or asks for external files like images, css or other script files.

If you are trying to include some extra javascript ,than you can add extra script tag in the head programatically. If you want to do something on the server, you can call a script on a server just as easily.

Here is how you can exeecute that script from javascript only if the if is true:

...
if (!flag){
    xmlHttp = new XMLHttpRequest();
    xmlHttp.open( "GET", "http://link/to/your/code.php?and=special&parameters=sent", false );
    xmlHttp.send( null );

    document.getElementById('more').innerHTML += xmlHttp.responseText;
    document.getElementById('more').style.visibility='visible';
    flag=true;
    }
...

edited Sep 24, 2012 at 14:58

answered Sep 24, 2012 at 14:32

nana

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10 Comments

Shady Over a year ago

I see, now I fully understand it. so what approach should I use? am very new to Javascript.

nana Over a year ago

Well it depend really on what are you trying to do, explain your goal and I will do my best to help you. Tell us what is in code.php

Shady Over a year ago

well , does it matter what's in it? cuz eventually I want to execute php code. But what I want is how to trigger this php code ONLY when the condition in the code above is true. what's in the php code, is simply connection to database , update some values (and deleting if necessery).

nana Over a year ago

There is a difference between running the code.php at the same time as generating the site thou and between calling it later like this (see my post edit). If you request it later from js code.php doesn't have access to variables you set and were working with while you were rendering the page. So you will have to connect to database again for example.

Shady Over a year ago

Ok, I think I got everything I need, will modify my code now :) , there's no need to use any "Ajax" library or such I guess.

|

Weacked · Accepted Answer · 2012-09-24 14:34:43Z

3

The php code is server side so it's executed before the javascript so javascript CAN'T control what php does. You need to use an Ajax script to make javascript can request a php file from the server, and then it'll work.

answered Sep 24, 2012 at 14:34

Weacked

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3 Comments

Shady Over a year ago

Ok, am new to javascript, and don't rly know what Ajax do or how to use it , but thank you very much for your help, will do my homework

Shady Over a year ago

can you please tell me how to use Ajax? , like what function will I need to do wt u suggest, will narrow down my searches

Weacked Over a year ago

You should definitly use Jquery lib, i'll make your work easier. Then just search for jquery ajax

mark · Accepted Answer · 2012-09-24 14:32:30Z

1

You can't do it that way... you said it yourself, PHP is server-side. In order to run PHP, you have to have the browser query something against your web server. This will most definitely not work as you intended... it'll always be included:

innerHTML +="<?php include_once('../../Includez/Traffic/Traffic_Code.php'); ?>";

You can, however, cause the JavaScript to fetch something more from the server which can run some PHP code and return something new to your page...

answered Sep 24, 2012 at 14:32

mark

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Comments

No name · Accepted Answer · 2016-12-15 14:53:44Z

0

Did you try solution with "load"?

<div id="special_block"></div>

<script>

   var a = 1;

   if (a == 1){
     $('#special_block').load('code.php');
   }

</script>

edited Dec 15, 2016 at 14:53

answered Dec 15, 2016 at 9:18

No name

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