Develop Reference

Multiple random images per page, without repeat

So, I need to display 2 or 3 different images in a website, as simple parallax dividers for content.
I have an array of 4 images, so I'll be able to randomize without repeat them in the same page, althoug the random won't be that noticeable.
I've been lurking this for a while, and found these
Random Image Display, Without Repeat, with Javascript
<script language="javascript">
var imagesArray = [
'images/img-1.jpg',
'images/img-2.jpg',
'images/img-3.jpg',
'images/img-4.jpg',
'images/img-5.jpg',
];
var usedImages = {};
var usedImagesCount = 0;
function displayImage() {
var num = Math.floor(Math.random() * (imagesArray.length));
if (!usedImages[num]) {
document.canvas.src = imagesArray[num];
usedImages[num] = true;
usedImagesCount++;
if (usedImagesCount === imagesArray.length) {
usedImagesCount = 0;
usedImages = {};
}
} else {
displayImage();
}
}
</script>
(this was created to exhibit the image upon a click on a button, as it follows
<input onclick="displayImage();" type=button value="Click Here">
I tried to adapt it to my need, but the call on my page din't produce any results)
https://www.daniweb.com/programming/web-development/threads/266181/random-imageslinks-without-repeating
(this one, I couldn't quite understand why, but I wasn't able to apply the solution. not sure if it's the code or the way of calling the image that's wrong...)
http://www.utopiamechanicus.com/article/not-so-random-image-rotation-in-php-for-html-the-sequel/
<?php
// rotate images randomly but w/o dups on same page - format:
// <img src='rotate.php?i=0'> - rotate image #0 - use 'i=1'
// for second, etc
// (c) 2004 David Pankhurst - use freely, but please leave in my credit
$images = array(// list of files to rotate - add as needed
"img1.gif",
"img2.gif",
"img3.gif",
"img4.gif",
"img5.gif");
$total = count($images);
$secondsFixed = 10; // seconds to keep list the same
$seedValue = (int) (time() / $secondsFixed);
srand($seedValue);
for ($i = 0; $i < $total; ++$i) { // shuffle list 'randomly'
$r = rand(0, $total - 1);
$temp = $images[$i];
$images[$i] = $images[$r];
$images[$r] = $temp;
}
$index = (int) ($_GET['i']); // image index passed in
$i = $index % $total; // make sure index always in bounds
$file = $images[$i];
header("Location: $file"); // and pass file reference back
?>
(this one was supposed to work calling through:
<img src='mysite.com/rotate.php?i=0'>
but the images are still repeating themselves sometimes)
They didn't work for me, so I decided to start a new topic, because I'm really newbie (actually, I don't know writing nothing at all) at javascript, and can't figure out what's the best approach. I understood it would be something like randomize the items, assign each of them a position (a number, a character, a [i], etc), and then call for it in my php page. Could you guys please help me?

Not sure is that you want but this will give you randomized images (without repeat) on a page, every time different ones:
<?php
$img = array('img1.png', 'img2.png', 'img3.png', 'img4.png', 'img5.png', 'img6.png');
shuffle($img);
for($i=0; $i<3; $i++){
print '<img src="'.$img[$i].'"><br>';
}
?>
If you want to receive one image per call, one of the possible solutions is to use session:
image.php:
<?php
session_start();
function getImage() {
$img = array('img1.png', 'img2.png', 'img3.png', 'img4.png', 'img5.png');
shuffle($img);
foreach($img as $key => $val) {
if (!is_array($_SESSION['img'])) {
return $val;
} elseif (count($_SESSION['img']) >= count($img)) {
$_SESSION['img'] = array();
}
if (is_array($_SESSION['img']) && !in_array($val, $_SESSION['img'])) {
return $val;
}
}
}
?>
page.php:
<?php
include 'image.php';
for ($i = 0; $i < 3; $i++) {
$currImg = getImage();
$_SESSION['img'][] = $currImg;
echo $currImg . '<br>';
}
?>
All displayed images are stored into SESSION variable. When all images are displayed, this SESSION var is reset and will start a new cycle.

Load and display new Messages correctly

I have a question:
I'm trying to create a Personal-Message-System on my Website and for this one my Idea was, that the user gets displayed the amount of new messages in each chat...
As in this screenshot
Yes, I am from germany, so the language in the screenshot is german...
You see the red "box" with the number in it? This one I want to create for each chat and I don't know how. With PHP only this would be easy, but I want, that the numbers are right always and refreshes automaticly...
So my HTML-Code is:
<div class="chat_body">
<a href="index.php?section=pn&mode=loadConversation&ConversationID=<?php echo $conversation['id']; ?>">
<div class="user" id='<?php echo $i ?>' data-user-id='<?php echo $user_id?>' data-conv-id='<?php echo $conversation['id'] ?>'>
// Displaying the name, etc... (for clarity i left it out)
<?php
echo "<div class='rightCountUnreadMessages'>";
echo '<div class="badge" id="badge-'.$i.'"></div>';
echo "</div>";
?>
</div>
</a>
</div>
At the top of the page my Javascript, to load the numbers, is:
jQuery(document).ready(function() {
//jQuery(setInterval(function() {
friends_count = document.getElementsByClassName("user").length;
for(var i=1; i < friends_count+1; i++) {
el = document.getElementById(i);
conv_id = el.getAttribute("data-conv-id");
user_id = el.getAttribute("data-user-id");
test = i;
jQuery.post('./Bauteile/Accounts/loadCounts/loadPNCount.php', {user_id_loadPN: user_id, conv_id: conv_id}, function(result){
console.log(result);
console.log(test);
if(result > 99) {
result = "99+";
}
if(result > 0 || result == "99+") {
document.getElementById("badge-"+test).innerHTML = result;
}
})
}
//}, 500));
});
And in the requested document in Javascript has the following content:
<?php
$conv_id = $_POST['conv_id'];
$from_id = $_POST['user_id_loadPN'];
echo (int)mysql_result(mysql_query("SELECT COUNT(*) FROM `messages` WHERE `group_id` = $chat_id AND `from_id` = $from_id AND `read_on` is NULL"), 0);
?>
I know it is difficult to see through all of this, but I hope someone can help me...
I don't know what I do wrong, but the code doesn't work...
I think it is probably because of the for loop but I don't know, how I fix this...
If you have questions please ask...
Thank you in advance

The problem is you have something asynchronous in your loop. To solve this problem you need a closure. You need to wrap the content of the for loop in a function that takes i as a parameter, then call the function in the loop.So try something like this :
function doClosure(i) {
var el = document.getElementById(i),
conv_id = el.getAttribute("data-conv-id"),
user_id = el.getAttribute("data-user-id"),
test = i;
jQuery.post('./Bauteile/Accounts/loadCounts/loadPNCount.php', {user_id_loadPN: user_id, conv_id: conv_id}, function(result){
console.log(result);
console.log(test);
if(result > 99) {
result = "99+";
}
if(result > 0 || result == "99+") {
document.getElementById("badge-"+test).innerHTML = result;
}
});
}
for (var i = 1; i < document.getElementsByClassName("user").length+1; i++) {
doClosure(i);
}

Addition to my post:
I replaced
jQuery.post('./Bauteile/Accounts/loadCounts/loadPNCount.php', {user_id_loadPN: user_id, conv_id: conv_id}, function(result){
with
console.log(user_id + " " + i);
jQuery.post('./Bauteile/Accounts/loadCounts/loadPNCount.php', {user_id_loadPN: user_id, conv_id: conv_id}, function(result){
console.log(result + " " + i);
for debugging...
The console output was:
21 1 line: 254 (= first console.log in this example)
26 2 line: 254
27 3 line: 254
26 4 line: 256 (= sec. console.log in this example)
27 4 line: 256
21 4 line: 256
So, as i suspected the For-loop and the jQuery function doesn't work together very well...

how to fix undefined variable in php?

I have an index.php page. The function of this page is infinite scrolling using AJAX, PHP and MySQL. The top portion contains PHP MySQL codes and bottom contains JavaScript.
I want to print the total number of rows in center of the page, but every time I try it shows "undefined variable" error.
I think when loading the page, the total number of variable tries to print first and then the PHP query takes place, so it shows "undefined variable", but when I put the total number of variable inside the PHP codings, there is no problem.
How can I prevent this?
My index.php is
//my php part here
<?php
if(isset($_POST["anotherID"])){
require_once("config.php");
$limit = (intval($_POST['limit']) != 0 ) ? $_POST['limit'] : 10;
$offset = (intval($_POST['offset']) != 0 ) ? $_POST['offset'] : 0;
$id = $_POST["anotherID"];
$query = $id;
$sql = "SELECT SQL_CALC_FOUND_ROWS * FROM x where title like '%xx%' ORDER BY rand() LIMIT $limit OFFSET $offset";
try {
$stmt = $DB->prepare($sql);
$stmt->execute();
$results = $stmt->fetchAll();
$row_object = $DB->prepare("Select Found_Rows() as rowcount");
$row_object->execute();
$roww_object =$row_object->fetchobject();
$actual_row_count = $roww_object->rowcount;
} catch (Exception $ex) {
echo $ex->getMessage();
}
if (count($results) > 0) {
foreach ($results as $res) {
echo'something';
}
}
$count = $actual_row_count;
exit;
}
?>
//my html part here
<html>
//some html codes
<?php echo $count; ?>
//some html codes here
//my java scripts here
<script type="text/javascript">
var busy = false;
var limit = 6
var offset = 0;
var anotherID = 5
function displayRecords(lim, off) {
$.ajax({
type: "POST",
async: false,
data: "limit=" + lim + "&offset="+ off+"&anotherID="+anotherID,
cache: false,
beforeSend: function() {
$("#loader_message").html("").hide();
$('#loader_image').show();
},
success: function(html) {
$("#results").append(html);
$('#loader_image').hide();
if (html == "") {
$("#loader_message").html('<button class="btn btn-default btn-block" type="button">No more records.</button>').show()
} else {
$("#loader_message").html('<button class="btn btn-default btn-block" type="button"><div id="loader_image"><img src="loader.gif" alt="" width="24" height="24">Loading please wait...</button>').show();
}
window.busy = false;
}
});
}
$(document).ready(function() {
// start to load the first set of data
if (busy == false) {
busy = true;
// start to load the first set of data
displayRecords(limit, offset);
}
$(window).scroll(function() {
// make sure u give the container id of the data to be loaded in.
if ($(window).scrollTop() + $(window).height() > $("#results").height() && !busy) {
busy = true;
offset = limit + offset;
// this is optional just to delay the loading of data
setTimeout(function() { displayRecords(limit, offset); }, 500);
// you can remove the above code and can use directly this function
// displayRecords(limit, offset);
}
});
});
</script>
//some html codes her
</html>
I know when a page is loading, the HTML parts are first loaded and then my jQuery stimulates the PHP part and then my results appear.
How can I fix this?
Why does $count always show "undefined variable"?
Thanks in advance.

You get an error of undefined $count because $count is defined only inside the if statement.
When the if clause doesn't apply $count is not defined.
Add an else clause to the if and initialize $count=0; and it will solve your problem.
Example:
....
$count = $actual_row_count;
exit;
}
else $count = 0;
?>

Why doesn't this JavaScript function calculate correctly when the site is first loaded, but works fine afterwards?

I am working on a site that generates notation for a random musical rhythm based on some user-selected parameters. It does this by using an ajax call, which returns a random set of <img> elements that represent different notes. I have a function that is designed to scale the rhythm to fit in the screen, regardless of it's actual size.
The function is triggered after a successful ajax call, which is triggered by a click event on a button.
My problem is that the function does not work as desired when running the first time the page is loaded.
After the function runs for the first time, the height attribute of all of the <img> elements is somehow set to 0.
However, the function works great if I run the it again (by clicking the button). It also works fine after a page refresh.
Also, I do not have this issue in IE11, only Chrome (I haven't tested other browsers yet).
I have tried wrapping the code in both $(window).load() and $(document).ready() event handlers, but this didn't help.
The site in action can be found at http://www.rhythmrandomizer.com
Any help would be greatly appreciated!
Below is the relevant code:
Event handler for the button:
$("#randomize").click(function(){
//get general options from form
var timeSignature = $("#timeSignature").val();
var phraseLength = $("#phraseLength").val();
//get note options from form
var checked = [];
$("#noteOptions :checked").each(function() {
checked.push($(this).val());
});
//alert user and exit function if nothing is selected
if (checked.length < 1) {
alert("Please select at least one note value");
return;
}
//format note option ids into a delimited string
var noteOptions = "";
for (var i=0; i < checked.length; i++) {
noteOptions += checked[i] + "a";
}
//remove the final comma and space
noteOptions = noteOptions.substr(0, noteOptions.length - 1);
//ajax call
$.ajax("randomize.php", {
data : {
timeSignature : timeSignature,
phraseLength : phraseLength,
noteOptions : noteOptions
},
type : "GET",
success : function(response) {
$("#rhythm").html(response);
scaleRhythm();
},
error : function(xhr, status, errorThrown) {
console.log(status + " | " + errorThrown);
}
});
});
The php file that returns the rhythm notation:
<?php
//MySQL connection variables
$hostname = 'localhost';
$user = ini_get('mysqli.default_user');
$pw = ini_get('mysqli.default_pw');
$database = 'rhytxfpd_rhythmrandomizer';
//Connect to database
try {
$db = new PDO('mysql:host=' . $hostname . ';dbname=' . $database,$user,$pw);
} catch(PDOException $e) {
echo $e->getMessage();
die();
}
//Get values from GET
$timeSignature = $_GET['timeSignature'];
$phraseLength = $_GET['phraseLength'];
$noteOptString = $_GET['noteOptions'];
//Split up note options string
$noteOptions = explode('a', $noteOptString);
//Create sql query
$sql = 'SELECT
noteName,
noteValue,
noteGraphic
FROM
notes
WHERE';
//append noteOptions as WHERE clauses
foreach ($noteOptions as $opt) {
$sql = $sql . ' noteGroupID = ' . $opt . ' OR';
}
//remove final " OR"
$sql = substr($sql, 0, strlen($sql) - 3);
//query the database and get all results as an array
/* This will return a table with the name, graphic, and value of
* the notes that the user selected prior to submitting the form
*/
$stmt = $db->query($sql);
$result = $stmt->fetchAll();
//Get the total number of options selected
$numOpts = count($result);
/***************************/
/** BEGIN PRINTING RHYTHM **/
/***************************/
//div to begin the first measure
echo '<div class="measure" id="m1' . $measure . '">';
//Print time signature
echo '<img class="note" src="notes/' . $timeSignature . '.png" title="time signature ' .
$timeSignature . '/4" alt="time signature ' . $timeSignature . '/4"/>';
//Prints as many measures as indicated by the phrase length selection
$measure = 1;
while ($measure <= $phraseLength) {
//begin a new div for other measures.
if ($measure != 1) {
echo '<div class="measure" id="m' . $measure . '">';
}
//Prints random measure according to time signature
$beats = 0;
while ($beats < $timeSignature) {
//Generate a random number
$random = rand(0, $numOpts - 1);
//Get the random note from results
$note = $result[$random];
//Continues if chosen note will not fit in the measure
if ($beats + $note['noteValue'] > $timeSignature) {
continue;
}
//Prints random note
echo '<img class="note" src="notes/' . $note['noteGraphic'] . '.png" title="' .
$note['noteName'] . '" alt="' . $note['noteName'] . '"/>';
//Adds random note's value to total number of beats
$beats += $note['noteValue'];
//$beats++;
}
//If last measure
if ($measure == $phraseLength) {
echo '<img class="note" src="notes/1.png" title="double barline" alt="double barline"/>';
echo '</div>';
} else {
echo '<img class="note" src=notes/b.png title="barline" alt="barline"/>';
echo '</div>';
}
//Increment to next measure
$measure++;
}
The scaleRhythm() function:
function scaleRhythm() {
//Get width of rhythm at full resolution
var rhythmWidth = $("#rhythm").width();
//Get current screen/window width
var screenWidth = window.innerWidth;
//Compute ratio between curren screen and window widths
var ratio = screenWidth / rhythmWidth;
//Multiply img note height by ratio, then by 90% to provide some
//breathing room on either side of the rhythm
var newHeight = (400 * ratio) * .9;
//Set img note height to new height or 300px, whichever is smaller
if (newHeight < 300) {
$(".note").css("height",newHeight);
//code to center rhythm horizontally
$("#rhythm").css("margin-top",(300-newHeight)/2);
} else {
$(".note").css("height",300);
$("#rhythm").css("margin-top",0);
}
}

Add this javascript to your <script></script>:
$(function(){ $("#randomize").click(); });
This will cause your page to run the function that populates your random elements then (at the end of that function) run the scale function.
I tested it by running it on your page in the chrome console and it worked.

If you put a breakpoint in the scaleRhythm function you'll notice on page load it's not being run. You've defined the function but it is not being called on page load. In fact none of the code you want run (ie: the ajax call) gets called until the first click happens. So what you need to do is trigger the click event on the button like JRulle said.
$("#randomize").click();

Okay so here is your issue.
The first time you click the button, var rhythmWidth = $("#rhythm").width(); evaluates to "0" because it is empty.
Which causes these subsequent functions to be "0" as well:
var ratio = screenWidth / rhythmWidth;
var newHeight = (400 * ratio) * .9;
I would edit your function to be like so:
var rhythmWidth = $("#rhythm").width();
if (rhythmWidth == 0) { rhythmWidth = 10; } //assign some reasonable value here
since your function does not support a rhythmWidth of "0"

issues with ajax and javascript when trying to count marks

I am having an issue with my javascript. I am trying to count marks for each correct chosen answer which is determined from db. If incorrect answer then marks is '0', else mark is dependent on answer's mark in db.
But I am having issues with the javascript:
First of all where it says connect.php, this just simply navigates to page where it connects to db, but is this correct or am I suppose to link to page where it will run query looking up answer's marks?
Second it says I have undefined response in my code and I do not what this should be called.
My question is can I have clarification for the above 2. I am trying to use ajax and javascript and will appreciate if a strong programmer can tackle this issue I am having and be able to correctly set up the code so that it is able to count each correct answer marks.
I have a jsfiddle which I am trying to follow but if somebody can edit fiddle to have a dummy version working for counting marks and then be able to provide code snippet stating what the proper code should be, then this will help me very much.
At moment the jsfiddle determines if answers selected are correct or incorrect and fiddle is here: http://jsfiddle.net/bWthd/3/
Actual code:
PHP/HTML:
$qandaquery = "SELECT q.QuestionId, Answer, AnswerMarks, OptionType
FROM Question q
INNER JOIN Answer an ON q.QuestionId = an.QuestionId
INNER JOIN Option_Table o ON q.OptionId = o.OptionId
WHERE SessionId = ?
GROUP BY q.QuestionId
ORDER BY RAND()";
...
$qandaqrystmt->bind_result($qandaQuestionId,$qandaAnswer,$qandaAnswerMarks,$OptionType);
$arrQuestionId = array();
while ($qandaqrystmt->fetch()) {
$arrQuestionId[ $qandaQuestionId ] = $qandaQuestionId;
}
foreach ($arrQuestionId as $key=>$question) {
?>
<div class="queWrap" data-q_id="<?php echo $key; ?>">
$options = explode('-', $arrOptionType[$key]);
if(count($options) > 1) {
$start = array_shift($options);
$end = array_shift($options);
do {
$options[] = $start;
}while(++$start <= $end);
}
else{
$options = explode(' or ', $option);
}
if($arrReplyType[$key] == 'Single'){
foreach($options as $indivOption) {
echo '<div class="ck-button"><label class="fixedLabelCheckbox"><input type="radio"
name="options_<?php echo $key; ?>[]" id="option-' . $indivOption . '" value="' .
$indivOption . '" /><span>' . $indivOption . '</span></label></div>';
}
}else if($arrReplyType[$key] == 'Multiple'){
foreach($options as $indivOption) {
echo '<div class="ck-button"><label class="fixedLabelCheckbox"><input type="checkbox" name="options_<?php echo $key; ?>[]" id="option-' . $indivOption . '" value="' . $indivOption . '" /><span>' . $indivOption . '</span></label></div>';
}
}
<p><input type='text' class='questionIds' name='questionids' value='<?php echo htmlspecialchars($arrQuestionId[$key]); ?>' /></p>
}
JAVASCRIPT/AJAX:
$(function() {
$('.queWrap .ck-button').change(function() {
var $ch_box = $(this),
$qwrap=$ch_box.closest('.queWrap')
q_id = $qwrap.data('q_id'),
val = $ch_box.val();
var dataToServer = {
q_id: q_id,
valueSelected: val
}
$.post('connect.php', dataToServer,function(){
var status=response.status
$qwrap.find('.status').text( status).addClass(status);
if( status=='correct'){
updateScore( response.points)
}
})
})
function updateScore( newScore){
var score= $points.data('score')+newScore;
$points.data('score',score).text( 'Score: '+score)
}
});
UPDATE:
Current code:
function update() {
var score = 0;
$('.queWrap').each(function(element) {
var $qwrap = $(element),
q_id = $qwrap.data('q_id'),
val = $qwrap.find('input:checked').val();
var dataToServer = {
q_id: q_id,
valueSelected: val
}
$.post('connect.php', dataToServer,function(response){
var status = response.status
$qwrap.find('.status').text(status).addClass(status);
if (status == 'correct'){
score += response.points;
$points.data('score', score).text('Score: ' + score);
}
})
});
}
...
//HTML
<div class="status"> </div>
Ok there is no errors but there is no marks appearing and calculating. Is it because of the connect.php I included in the javascript function. Do I need to navigate to page which connects to db connect.php or navigate to a page where it runs a query on finding answer marks for each selected answer? I am running out of time so can you please implement the code for me asap because I have to get this finished. I want the following to happen:
Count marks for each answer selected, if incorrect answer selected then value is 0 for those answers, if correct answer then it's marks are determined from database. Howcan I get each correct answer button to contain it's own answerId?
To determine answerId we can use the questionId displayed in text input (See PHP/HTML code snippet at top) and then depending on values of each answer button, retrieve the answerid matching the answer values for each question.
Below is example database showing Answer Table
AnswerId (auto PK) QuestionId Answer AnswerMarks
1 72 A 2
2 72 C 1
3 73 B 2
4 73 C 2
5 73 E 1

Your updateScore function works wrong. You should store the points for each question in a data element, and in the updateScore() function you should add all these up, and put the sum into the $points element. Something like this:
$(function() {
$('.queWrap .ck-button').change(function() {
update();
});
function update() {
var score = 0;
$('.queWrap').each(function(element) {
var $qwrap = $(element);
var q_id = $qwrap.data('q_id');
var val = $qwrap.find('input:checked').val();
var dataToServer = {
q_id: q_id,
valueSelected: val
};
$.post('connect.php', dataToServer, function(response){
var status = response.status
$qwrap.find('.status').text(status).addClass(status);
if(status == 'correct'){
score += response.points;
$points.data('score', score).text('Score: ' + score);
}
});
});
}
}
And this function should be invoked on every change of the answers. (I am not sure this works just an example).