I'm new with php and I'm facing very difficult on understanding how it works. I work with C# windowsForm and Asp.Net so that's why i'm having so much difficult.
I have a form:
<html>
<head><title>Numero 1</title></head>
<body>
<form method='post' action="01.php">
Valor da Conta de Luz <input type="text" name="Valor" />
<input type="submit" value="Verificar Valor" onclick="ValorConta()" />
</form>
</body>
</html>
And in the same file i have my php
<?php
function ValorConta()
{
$TxtValor = $_POST["TxtValor"];
if($TxtValor > 50)
{
echo "Você está gastando muito !";
}
else
{
echo "seu gasto é normal !";
}
}
?>
I want to call this method ValorConta by the click of my button, and pass as parameter the value of the textbox... It's so easy with C# but now I have no idea how to do this... And my teacher is not going so well explaining it to me. Any help ?
Short answer: with an AJAX call to the PHP script, specifying parameters that allow you to execute that certain method. That's because the PHP script is interpreted before you get the actual page and all the PHP code is executed. Then, JS methods cannot execute any PHP code because, as you can see if you check the source code of the page you get in the browser, there is none left in your page!
Hence, given the fact you're mixing the function containing some logic, with some presentation output, you have to separate them in two php scripts. Then, the AJAX call with get only the ouput you need.
You must write your new PHP script aiming at receiving parameters that definbe which method to execute and with what data as parameters.
If your PHP file containing the function ValorConta() is called 01.php and located in the same directory as your HTML file, this should just work.
Be aware however, that PHP is executed on the server, not on the client. So you can't use onclick to call a PHP function. The only thing that can trigger a PHP function is a new HTTP request to a PHP script calling that function. This can for example be achieved by sending a form via POST as you do in your HTML file.
Related
I am trying to hide our mailing address on our website, until someone cliks a button to "load" the address. I am doing it like follows:
Homepage.php:
<button onclick="test()"> Click </button>
<div> </div>
<script>
function test(){
$.ajax({url:"address.php", success:function(result){
$("div").text(result);}
})
}
</script>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.2.4/jquery.min.js"></script>
Address.php:
<?php
function php_func(){
echo '<span><?php echo $address; ?></span>';
}
php_func();
?>
This works in echoing the text onto homepage.php, but it's not loading the PHP function. Just showing the function as text as seen here:
I tried $("div").write(result);} and it won't even load.
$address is already defined elsewhere. Any tips?
You're trying to write code which outputs code which outputs the address. Why? You're already in the context of outputting something from the PHP code:
echo "something...";
If what you want to output is the value of $address then just output that:
echo "<span>$address</span>";
I suspect the reason you did it that way is because you're expecting the currently loaded page to parse and execute that PHP code. This is a fundamental misunderstanding of how these technologies work. The PHP code for that page executed once, on the server, and delivered the resulting HTML/CSS/JavaScript to the client.
The AJAX operation is making a new, separate request to another PHP resource which will execute on the server and output back to the client. In this case it's just outputting a string value, which the client-side JavaScript code will then write to an element on the page:
$("div").text(result);
(This is a good opportunity for you to use your browser's debugging tools and observe the AJAX request/result in the network tab, to see what's actually being sent/received. At no point should actual PHP code be visible to the browser. All of that is executed on the server.)
The reason this is important is because, if this is the case, then you are likely misunderstanding where $address is defined. If it's defined in the PHP script which rendered the page you're looking at, that doesn't mean it's defined in address.php. If the code you're showing us for address.php is the entirety of that page then $address is not defined.
So you'll need to define $address on that page.
After having said all of that... You might find it much easier not to involve AJAX for this at all in the first place. Just output the address to the page but style the <span> to not be visible. Then when the user clicks the button, make it visible. No need for the complexity of an entirely new HTTP request:
$('button').click(function () {
$('span').show();
});
span {
display: none;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<button>Click</button>
<span>this is the address</span>
You don't use <?php echo inside strings; that's only used when you're in a section of the script that's outputting literal text, not executing PHP code.
If you're in PHP code doing echo, you use variable substitution or concatenation.
<?php
function php_func(){
echo "<span>$address</span>";
}
php_func();
?>
You'll need additional code to set the $address variable; I assume you just left that out for simplification in the question.
<?php
function php_func(){
echo '<span>' . $address .'</span>';
}
php_func();
?>
this should work, u can't use 'echo' and inside echo open 'php' tag to use again.... more another 'echo'
This question already has answers here:
What is the difference between client-side and server-side programming?
(3 answers)
Closed 7 years ago.
So now i now this was a dumb question but does anyone now the best way to solve it without an ajax request, becaus I think it would be stupid to make a new file for just one line of code
I am making a gallery and I want two types of views one grid-view and a slide view. My slide and my grid view both work but they stand in different files. So I wrote a simple jquery function to load some php code into the html code. So that when I click a button the html code dissappears and there is php code. The jquery funtion works but the problem is that when the code is changed it doesn't recognise it as php code but just as a string.
This is what I see, you can see the text but it needs to execute that code:
Here is the jquery function:
$(document).ready(function(){
$("img.grid_icon").click(function() {
$(".werkvenster").html("<?php include_once('resources/UberGallery.php'); $gallery = UberGallery::init()->createGallery('img/gallerij/'); ?>");
})
});
I use the < and >, otherwise the browser sees it as php code it has to execute instead of seeing it as a string.
Here is the html code it has to be in:
<body>
<section class="werkvenster">
<img src="img/website/icon_grid.png" height="30px" class="grid_icon">
<div class="galerij" id="galerij">
</div>
<button class="omlaag" id="galerij_knop">Terug</button>
<button class="omhoog" id="galerij_knop">Verder</button>
</section>
</body>
So everything between the section tags with class "werkvenster" needs to be changed by
<?php include_once('resources/UberGallery.php'); $gallery = UberGallery::init()->createGallery('img/gallerij/'); ?>
When someone clicks on the grid icon.
Thanks a lot in advance and please don't mark this as a duplicate because I have been searching for over an hour to find an answer to this question.
It seems you need some clarification how PHP and JS work.
a) PHP-code is executed on the server-side. all of it. and nothing else
b) The output, completely free of PHP, is sent to the browser
c) JS-code is executed on the client-side. all of it. and nothing else
If you use JS to write PHP-code, it only happens inside the browser, which doesn't know what to do with it. and long after every bit of PHP-execution.
You do NOT write anything back to the server with this.
what you CAN do is to do an AJAX-request to a specific PHP file that returns your desired output. but you can't just mix JS and PHP like that. it just doesn't work.
edit: in response to your edit about how to solve the problem without using AJAX
to put it simply: not at all. you have to get the data from the server, the best way to do this is AJAX (it was made for this and nothing else) and on the server you have to generate the data somehow. and the cleanest way is a new file.
it doesn't recognise it as php code but just as a string
That's because it is a string:
"<?php include_once('resources/UberGallery.php'); $gallery = UberGallery::init()->createGallery('img/gallerij/'); ?>"
PHP doesn't run in the browser, it runs on the server. By the time the page is delivered to the browser, the PHP code has executed and completed and produced its output. PHP is no longer involved after that point.
If you want to execute code client-side, that's what JavaScript is for. If you need code to execute server-side, the browser will have to make a request to the server to make that happen. A page load, a form post, AJAX, etc. They all take the form of an HTTP request (potentially with some data sent to the server) which invokes a PHP script and receives that script's output as the response.
You could do what you are trying to do without ajax. You just have to create a hidden <section> that contains the php code (which you have to do on the server-side before it gets sent to the browser). And then in the browser, use jquery to get the contents from the hidden <section> (or just swap the sections)
Here is an example:
Server-side PHP:
<body>
<section class="werkvenster">
<img src="img/website/icon_grid.png" height="30px" class="grid_icon">
<div class="galerij" id="galerij">
</div>
<button class="omlaag" id="galerij_knop">Terug</button>
<button class="omhoog" id="galerij_knop">Verder</button>
</section>
<section id="hiddenStuff" style="display:none">
<?php include_once('resources/UberGallery.php'); $gallery = UberGallery::init()->createGallery('img/gallerij/'); ?>
</section>
</body>
jQuery:
$(document).ready(function(){
$("img.grid_icon").click(function() {
$(".werkvenster").html($("#hiddenStuff").html());
})
});
Sorry, this question must be repeated, it already asked the following link, but the answer is not cleared.. So can anyone please solve this problem???
exe not giving output in php
I am trying to call a Qt generated executable file through PHP code which fails to run the exe.. The same exe runs on double-click and through command line..
Below is my code
<?php
$exec_cmd = exec('"./myEXE"');
?>
<html>
<body>
<form>
<input type="submit" value="RUN" onclick="$exec_cmd"/>
</form>
</body>
<html>
Thank You...
PHP is a server side language. It means that the php code is compiled and executed in the server and the output is sent to the client.
What you are trying to do is to use PHP as client-side language, like JavaScript.
The porgram is executed when the page is displayed and you want it to be displayed once the user clicks on the button, for that you must use JavaScript.
I would use AJAX to make the request to the server so it can execute the program but if you don't want to use javascript you can set the form to redirect the page with a GET or POST parameter and check in PHP if that parameter is set
Here is what I'm trying to do...
$("div").prepend("<div id='comment-number'><?php the_comment_number(); ?></div>");
Is there some way to get this to work?
<div class="gallery-item">
<div class="comment-number"><!--?php echo htmlspecialchars(the_comment_number()); ?--></div>
</span>
<span class="gallery-icon">
<img src="http://mysite.com/test/wp-content/uploads/2011/06/fff-150x150.gif">
</span>
</div>
PHP is executed on the server, but JavaScript code (jQuery) is executed later, in the web browser. For that reason, PHP can produce JavaScript code, but JavaScript can't produce PHP code.
The <!--? in your posted output shows that something is filtering our your PHP code. So the problem isn't your PHP code, it's that you're not actually executing PHP code. If it's a .js file, PHP almost certainly can't be included.
If PHP were being evaluated (ex. if this were in a <script> tag in a .php file), this should produce valid JavaScript code that will do what you want:
$("div").prepend("<div id='comment-number'><?php echo htmlspecialchars(the_comment_number()); ?></div>");
1) php is SERVER side scripting
2) javascript is CLIENT side scripting (generally)
so this is what happens:
1) User opens up your page http://example/
2) Your CLIENT sends GET request to http://example/ server
3) Apache (given you run on it) captures the request, based on the server config approaches index.php (index.html, etc). If php is installed, your index.php will be parsed by mod_php module
<<<< this is where SERVER side scripting is activated
4) outcome of the parsing of index.php will be then transferred back to CLIENT
5) CLIENT will digest the outcome received by SERVER
6) If there are javascript calls, those are executed either immediately OR when document is loaded (based on approach)
That's it. Here normal request life ends.
NOW if you want your page to dynamically update some parts of it, here is how you do that:
1) Usually to update your page dynamically, you would use AJAX approach. When AJAX request is created, 2-7 happens again, but this time the caller is your ajax process and information which is received is sent back to that process to decided what to do with it.
Okay, some coding:
1) index.php
<!-- include jquery, etc //-->
<div id="comments"></div>
<script>
function fetch_comments(){
$.get("ajax.php", null, function(data)){
// this is called, when response from SERVER is received
$("#comments").prepend(data);
setTimeout("fetch_comments", 5000); // fetch again in 5 seconds
}
}
$(document).ready({
fetch_comments();
});
</script>
2) ajax.php
<?php
//fetch comments, return them for CLIENT
echo "<p>Comment on " . date("Y-m-d H:i:s") . "<br />Lorem Ipsum</p>";
This should help you understand the whole process. Did not test the code, but should be quite ok.
do a .ajax() query to PHP script that will provide you value of the_comment_number(); and put result to comment-number by $("#comment-number").prepend(result); on success event in ajax query.
Remebmer that PHP script have to have connection to database and pass to it all variables you need (like entity id, article id, page etc.). You can do it by GET or POST.
Request is sended by browser so session/cookies will be the same unless you changed it in current request.
PHP is executed on the server side so you cannot call it from javascript
You can try something like this which will render once the page loads
$("div").prepend("<div id='comment-number'>"+ <?php the_comment_number(); ?> +"</div>");
Couldn't you just add the value directly to the template instead of using javascriot? eg:
<div class="gallery-item">
<div class="comment-number"><?php echo (the_comment_number());?></div>
...
</div>
Also you have a </span> tag with out matching <span> tag in your example.
As already told, you can't produce or call php code from javascript directly(you need to make an ajax call or form submit). You need to make ajax call using jquery to fetch the comment number and then update it into div.
However, you may want to look at this library - http://www.phplivex.com/ .It may help you in doing things your way. It allows you to call user defined php functions in javascript using AJAX internally.
Reading through this disccussion and from what i understand you want to acheive.. You gotta figure how your page is served. If it is an .php file that is serving the content, then you wont need Javascript at all and could get your function call to work by adding the function between the div as so..
<div class="comment-number"><?php echo htmlspecialchars(the_comment_number()); ?></div>
Assuming you don't have access to the .php or if its a .html/htm page that serves the content then your only bet would be to use ajax. That is make an ajax call to a php file(on the same domain) that makes your function call and echos the comment no. The Ajax will retrieve the echo'd comment no. which you can append/prepend to the desired
I'm trying to assign value of JavaScript variable to php session. Please see my code below -
<script type="text/javascript">
<?php $_SESSION['historyClass'] = "";?>
var myClass = $(this).attr("class");
if(myClass == 'trigger'){
<?php $_SESSION['historyClass'] = "trigger"; ?>
}
else{
<?php $_SESSION['historyClass'] = "trigger active"; ?>
}
alert('<?php echo $_SESSION['historyClass']; ?>')
</script>
In myClass variable, i'm getting 2 values
1) trigger
2) trigger active
Whatever the value I'll get, I want to store it in php session. But when I alert the session value it is always giving me "trigger active". It means it is always going to else part. I have checked the 'if' condition by alerting in it, the control is going properly in "If" and "else" part.
What is the problem? Am I doing something wrong?
Thanks in advance.
PHP is processed first, and then javascript is executed, so it's impossible to directly assign values to php variables.
instead you could send http requests from javascript (Ajax) to php scripts to save your data.
This won't work. PHP is executed on the server, and JS on the client. That means that the php is running before the JS is parsed. I suggest you look at Ajax if you want to run PHP from javascript (specifically the jQuery library and its ".get()" function).
What's happening is that the PHP is parsed, and doesn't see any JS, so it runs as normal, and sets the session to trigger, and then trigger active. Then javascript comes along on the client, and the client doesn't see any PHP code,so doesn't run it.
this wont work. the php code runs on serverside, js - on client. so php is executed before the page is shown to the user. it means that first is executed $_SESSION['historyClass'] = "trigger"; than $_SESSION['historyClass'] = "trigger active"; and obviously the value will be trigger active
yes you are doing something wrong.
javascript runs on client side and php on server side. so your code runs first on server side and then on the client.
thats why you can't do it like you did. a common way to transfer javascript data to a php script is, writing the value to a hidden field, so that it gets submitted to the server.
just create a hidden field and fill it with a value from javascript
<script type="text/javascript">
function valToPHP(name,value){
document.getElementById(name).value = value;
}
</script>
...
</head>
<body>
<input type="hidden" id="myField" name="myField" value="" />
...
you can then read it in your php script like that
$_GET["myField"] or $_POST["myField"]
this depends on your method of the form