This is a part of the code in a 'process.php' file:
echo "<script type='text/javascript'> percYes = ".$yes."</script>"
echo "<script type='text/javascript'> percNo = ".$no."</script>"
This 'process.php' file runs in the background (using jQuery/ajax) when the user clicks a butto. The 'echoed' html above replaces the contents of a div. So essentially what I'm trying to do is update some Javascript variables using a background php call, the above solution does not seem to work though, i.e. the script is not being ran once it is placed in the div.
A bonus problem involves using these updated Javascript variables to update a graph. I have a workng javascript graphing function, but the problem is getting the new graph to replace the old one (or just update it, if that's possible).
Thanks.
If all you are trying to do is update some JS vars, you may be better off having your process.php file returning a json string:
$array = ('percYes' => $yes, 'percNo' => $no);
echo json_encode($array);
This will give you a json string that can be evaluated and used in a callback for your JS ajax call.
So if you have a var 'percYes' and 'percNo' in an accessible scope, your callback could look something like this:
function(jsonstr) {
obj = eval(jsonstr);
percYes = obj.percYes;
percNo = obj.percNo;
}
I hope this helps.
Related
The code looks like this:
PHP file
<?php
...
$arrayName = ['ArrayValue_0', ..., 'ArrayValue_n'];
...
php?>
JavaScript
$('.elementClass').each(function(index, id) {
$(id).html('<?php echo $arrayName[index - 1]?>');
});
But you can't just insert a JavaScript variable like that into php tags so index is never received.
I know this can be done via AJAX but is there any other way? Thanks in advance.
Additional info:
I've been told to do this in PHP so there's no posibility of switching the array to a JS file.
You can define arrayName variable in JS and initialize it with the value from the server:
var arrayName = <?php echo json_encode($arrayName); ?>;
$(".elementClass").each(function(index, id) {
$(id).html(arrayName[index-1]);
});
What you're trying to do will not work. For example this:
$(id).html('<?php echo $arrayName[index - 1]?>');
The above will never, ever work, because PHP is run on a server, not on your user's browser.
What you need to do is send the variable somehow to the server. You have a plethora of options:
Use a form and read a $_POST variable
Append it to a URL and read a $_GET variable
Use AJAX and asynchronously send that variable to the server
Return the whole array from PHP to your Javascript code
etc. etc.
Remember, PHP runs on the server, which renders the page, which then in turn is read by your browser where you run Javascript. You can't paste PHP code into the page and expect it to be parsed by PHP!
You need to get back to the server if you wish to get info from it (PhP runs on the server), so either you create a javascript variable on-the-fly when loading the page with the complete content of your PhP array , either you use ajax to get back to the server without refreshing the whole page.
I am trying to get the image links from 9gag (what also works) and when I click on a button the image changes to the next one. The basic problem is that it works only once. I can then switch between the 1st and the 2nd image, though. This should be pretty simple, but I ´ve got no clue where the error is, so thanks in advance to anyone bothering to look at this.
<?php
$index = 0
$html = file_get_contents("http://www.9gag.com");
preg_match_all( '|http://d24w6bsrhbeh9d\.cloudfront\.net/photo/.+?\.jpg|', $html, $gags);
?>
<script>
function nextImg(){
<?php $index++;?>
pic.src='<?php echo $gags[0][$index];?>';
}
function prevImg(){
<?php $index--;?>
pic.src='<?php echo $gags[0][$index];?>';
}
</script>
You can't increment your PHP variables after the page has loaded. You are trying to increment them client-side with JavaScript. You are going to need to call that PHP using AJAX if you want to do this without refreshing the page, and even then you'll want to increment a javascript variable to keep track of where you are.
EDIT: I went a little nuts creating an ajax routine using PHP and JavaScript, specifically the jQuery library, which you will need to link to for this to work. You may also need to modify parts of the script to work with what you're trying to accomplish, but this certainly is a guide for running your ajax app as you're hoping to.
Start by making a PHP file with this script:
<?php
// Set content header to json
header('Content-Type: application/json');
// Get the index from the AJAX
$index = $_GET['index'];
// Grab file contents & parse
$html = file_get_contents("http://www.9gag.com");
preg_match_all( '|http://d24w6bsrhbeh9d\.cloudfront\.net/photo/.+?\.jpg|', $html, $gags);
// Send filename back to AJAX script as JSON
echo json_encode(array($gags[0][$index]));
?>
Then, in your HTML, include this jQuery to complete AJAX calls to your PHP script, and update the DOM with the data from the PHP script.
<script>
$(function() {
'use strict';
// Initiate index variable
var index = 0;
// Load initial image
loadImage(index);
// Add click event to a button with class of next-btn
$('.next-btn').click(function(e) {
e.preventDefault();
// Increment index to get next image
index++;
// Run AJAX function to retrieve image
loadImage(index);
});
// Add click event to a button with class prev-btn
$('.prev-btn').click(function(e) {
e.preventDefault();
// Decrement the index if it isn't 0
if (index > 0) {
index--;
}
// Run AJAX function to retrieve image
loadImage(index);
});
});
function loadImage(index) {
'use strict';
$.ajax({
type: 'GET',
url: 'your-php-script.php', // Filepath to your PHP script
data: 'index='+index, // Index is passed through GET request
dataType: 'json', // Return JSON
success: function (data) { // If the php script succeeds
// Change img with class of pic's src
// to the filename retrieved from php
$('.pic').attr('src', data[0]);
}
});
}
</script>
Configuring this for your needs will require some serious PHP and jQuery/JavaScript knowledge, as some debugging will likely be needed. Good luck!
EDIT 2:
I uploaded the working (tested, it works) source files to my website if you want to download. Please accept answer and let me know you grabbed the files...
http://www.wedgewebdesign.com/files/ajax-image-loader.zip
#Eric basically has it right but didn't really go into detail if you aren't familiar with the model...
PHP is a server side language in that it does all its processing on the web host server and once it is complete sends a static result back to the user. This means, whatever you see after the page is loaded within PHP is there to stay, unless you do one of two things:
1) Send a new request -- You provide different parameters, the page re-executes its logic and returns a new result to the user
2) Execute some form of clientside Javascript. Javascript is different from PHP in that it executes on the client (not the server) so you don't necessarily have to send responses back to the server unless you need more information. Javascript and PHP can be combined to create AJAX calls which allow the client to make asynchronous calls to the webserver for more data without reloading the entire page. The Javascript handles re-drawing the new information or updating the page which can appear seamless to the user.
What you therefore need is one of those two options. Either you provide 'next'/'previous' links to the user and the page is loaded differently each time or you create an AJAX call that fetches the url of the next image and then loads it.
Try assigning a variable to $gags[0][$index]. Something like
$imgsrc = $gags[0][$index];
and then
pic.src='<?php echo $imgsrc; ?>';
I want the value of JavaScript variable which i could access using PHP.
I am using the code below but it doesn't return value of that variable in PHP.
// set global variable in javascript
profile_viewer_uid = 1;
// php code
$profile_viewer_uid=$_POST['profile_viewer_uid'];
this gives me the following error :-
A PHP Error was encountered
Severity: Notice
Message: Undefined index: profile_viewer_uid
Another php code i used which give empty value
$profile_viewer_uid = "<script language=javascript>document.write(profile_viewer_uid);</script>
When I echo it shows nothing.
Add a cookie with the javascript variable you want to access.
document.cookie="profile_viewer_uid=1";
Then acces it in php via
$profile_viewer_uid = $_COOKIE['profile_viewer_uid'];
You will need to use JS to send the URL back with a variable in it such as:
http://www.site.com/index.php?uid=1
by using something like this in JS:
window.location.href=”index.php?uid=1";
Then in the PHP code use $_GET:
$somevar = $_GET["uid"]; //puts the uid varialbe into $somevar
Here is the Working example: Get javascript variable value on the same page.
<script>
var p1 = "success";
</script>
<?php
echo "<script>document.writeln(p1);</script>";
?>
You might want to start by learning what Javascript and php are. Javascript is a client side script language running in the browser of the machine of the client connected to the webserver on which php runs. These languages can not communicate directly.
Depending on your goal you'll need to issue an AJAX get or post request to the server and return a json/xml/html/whatever response you need and inject the result back in the DOM structure of the site. I suggest Jquery, BackboneJS or any other JS framework for this. See the Jquery documentation for examples.
If you have to pass php data to JS on the same site you can echo the data as JS and turn your php data using json_encode() into JS.
<script type="text/javascript>
var foo = <?php echo json_encode($somePhpVar); ?>
</script>
If you want to use a js variable in a php script you MUST pass it within a HTTP request.
There are basically two ways:
Submitting or reloading the page (as per Chris answer).
Using AJAX, which is made exactly for communicating between a web page (js) and the server(php) without reloading/changing the page.
A basic example can be:
var profile_viewer_uid = 1;
$.ajax({
url: "serverScript.php",
method: "POST",
data: { "profile_viewer_uid": profile_viewer_uid }
})
And in the serverScript.php file, you can do:
$profile_viewer_uid = $_POST['profile_viewer_uid'];
echo($profile_viewer_uid);
// prints 1
Note: in this example I used jQuery AJAX, which is quicker to implement. You can do it in pure js as well.
PHP runs on the server. It outputs some text. Then it stops running.
The text is sent to the client (a browser). The browser then interprets the text as HTML and JavaScript.
If you want to get data from JavaScript to PHP then you need to make a new HTTP request and run a new (or the same) PHP script.
You can make an HTTP request from JavaScript by using a form or Ajax.
These are two different languages, that run at different time - you cannot interact with them like that.
PHP is executed on the server while the page loads. Once loaded, the JavaScript will execute on the clients machine in the browser.
In your html form make a hidden field
<input type="hidden" id="scanCode" name="SCANCODE"></input>
Then in your javascript update the field value by adding;
document.getElementById("scanCode").setAttribute('value', scanCode);
This could be a little tricky thing but the secure way is to set a javascript cookie, then picking it up by php cookie variable.Then Assign this php variable to an php session that will hold the data more securely than cookie.Then delete the cookie using javascript and redirect the page to itself.
Given that you have added an php command to catch the variable, you will get it.
You need to add this value to the form data that is submitted to the server. You can use
<input type="hidden" value="1" name="profile_viewer_uid" id="profile_viewer_uid">
inside your form tag.
I'm using jQuery to load the result of a PHP script into a variable. The script is passed something that the user typed with a GET request. I want to take just what the script spit out into its <body> tag. Here's what I've tried:
JS:
function loader() {
var typed = $('#i').val(); //get what user typed in
$.get("script.php", {i: typed}, function(loaded) {dataloaded = loaded;});
alert($(dataloaded).find('body'))
}
But it just displays [Objec object]. How can I get a useful value that is just the contents of the body of a loaded page?
I know the PHP works, I just need the JS.
The script echos something like 1!!2 (two numbers separated by two exclamation points).
Thanks!
You are trying to access the dataloaded which might not be assigned due to the asynchronous nature of AJAX calls. The only safe place to access it is inside the success callback. Also you could use the .html() function to get the contents of the body tag:
function loader() {
var typed = $('#i').val(); //get what user typed in
$.get('script.php', { i: typed }, function(loaded) {
alert($(loaded).find('body').html());
});
}
Also note that if the script.php only echoes 1!!2 without a <body> tag it won't work.
Without knowing what console.log prints it is hard to say, but try these
alert($(dataloaded).find('body').html());
Or
alert($(dataloaded).find('body').text());
I changed the page that I'm trying to fetch to XML. I'm using $.find to get each element of interest individually from the XML page, which suits this particular app well.
This problem has disappeared, as there is no longer a head section to ignore, and I'm just grabbing individual XML elements anyway.
Thanks for all your time and help!
Use JSON type. I am not sure about whether your Jquery script correct or not but using JSON with a correct usage would solve problem. ie.:
function loader() {
var typed = $('#i').val(); //get what user typed in
$.get("script.php", {i: typed}, function(loaded) {dataloaded = loaded;},"json");
alert($(dataloaded).find('body'))
}
And POST variable from script.php after encoding JSON. Use Php's json_encode() function. You need to create variable as an array. For example:
<?php
$title = 'Hello World';
$content = 'Get well soon Japan!';
$arr=array('title'=>$title,'content'=>$content);
echo json_encode($arr);
?>
And Jquery would be something like:
function loader() {
var typed = $('#i').val(); //get what user typed in
$.get("script.php", {i: typed}, function(loaded) {var dataloaded = loaded.title+" "+loaded.content;},"json");
$("body").html(dataloaded);
}
You may need to use Jquery's parseJson() functions on some situations. Don't think you will need here.
Is there any way I could get the value of a html text field without using GET or POST or REQUEST? Alternatively, is there any way to get the field value in the same form or page else where.
This works with direct value such as "james", "system" and so on. the only problem is how do i make it work with html field values
Like:
<input type = "submit" onclick = "
<?php $username = "kut";
$result = checkname($username);
if($result)
{
?> alert("success"); <?php
}
else {?> alert("failed"); <?php
}?>
">
How can i replace "kut" with the value of a text field with id = "username" ?
<?php $username = "?>document.getElementById('username').value;<?php"?>
or something like that...???
In short, I need to get the value of a html field else where in the same page inside a javascript function, using PHP... like in the above javascriptFunction(), function
You have fundamental misunderstanding of how client-server architecture works.
PHP can be executed thousands of miles away, even days apart, from place where and when JavaScript does.
First PHP generates whole page, all of HTML, all of JavaScript source code (unexecuted), and then, after PHP is done and gone, browser starts running JavaScript.
These two can't be mixed together like you wanted, even though it may seem so in the PHP source code.
Although you can communicate with the server again using AJAX or similar, you probably should first understand how client-server architecture works and try to solve the problem without AJAX (e.g. handle all of it on server side, or all on client side).
You can not directly call a PHP function in JavaScript. You could set a JavaScript value from php before the page loads via echo. PHP is executed on the server while JavaScript is executed on the client side.
1> I suggest using jQuery to handle the Ajax part.
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script>
function check_user(){
var user_el=document.getElementById('username');
if(!user_el){ return false; }
var username=user_el.value; // this could all be replaced with $('username').val()
$.getJSON('check_var.php',{"user":username},function(data){
if(data.result=='error'){ alert('something was wrong with the PHP stuff'); }
alert(data.userstatus);
});
}
</script>
2> On the PHP side, as check_var.php, you need a script that takes the username input, checks the DB, and sends back the result as JSON data.
<?php
if(!isset($_GET['user']){ exit; }
$username=preg_replace('#['^\w\d]#','',$_POST['user']);
//do your database query. I assume you have that part all set.
//since I'm not filling in all of that, you'll need to fix this next part to work with your system
//let's pretend it's like $found=check_user($username);
//be sure to use mysql_real_escape_string or prepared statements on the $username var since you're working with user input
$status=$some_db_error ? 'error' : 'success';
$results=array('result'=>$status,'userstatus'=>$found);
header('Content-Type: application/json');
echo json_encode($results);