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raldje

refresh image each 10 secondes

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Hi,

first sorry for my english, i'm french

i got a table in my database to announced events with this fields: id, event_date, announce, image.

I want to make a header with images changing each 10 secondes, but i don't want to refresh all the page.

 

This is what i use actually:

$rst = $bdd->query('SELECT image from matable order by Rand() LIMIT 0, 1');
while($donnees = $rst->fetch())
{
$image = nl2br($donnees['image']);
if (empty($image)) {
echo '<img src="imagedefaut.jpg" />';
}
else {
echo '<img src="image/'.$donnees['image'].'" alt="image"/>';
}         
}
$rst->closeCursor();

I know i have to use some javascript with setInterval but i don't know how to do.

Can i have some help, please.

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here is an eg :

<img src="./01.png" id='img1'/>
<img src="./02.png" id='img2'/>
<script>

var x=1;
        var myVar = setInterval(myTimer, 1000);

function myTimer() {
   if(x%2==0){
	document.getElementById("img1").style.display = "none";
	document.getElementById("img2").style.display = "block";
        x=1;
		}
	else{
	     document.getElementById("img2").style.display = "none";
	document.getElementById("img1").style.display = "block";
	x=2;
	}	
}
</script>

all you have to do is get some images and set the SRC path to the right location .

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You can use ajax to call the same php code, but replace the current with new targeting its parent container element, that way if javascript is disabled the original php code will run.

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$rst = $bdd->query('SELECT image from matable order by Rand() LIMIT 0, 1');
while($donnees = $rst->fetch())
{
$image = nl2br($donnees['image']);
echo '<img src="defaultimg.jpg" alt="image_by_default" id="img1"/>';
echo '<img src="image/'.$donnees['image'].'" alt="image" id="img2"/>';
}
$rst->closeCursor();

<script>

var x=1;
        var myVar = setInterval(myTimer, 1000);

function myTimer() {
   if(x%2==0){
	document.getElementById("img1").style.display = "none";
	document.getElementById("img2").style.display = "block";
        x=1;
		}
	else{
	     document.getElementById("img2").style.display = "none";
	document.getElementById("img1").style.display = "block";
	x=2;
	}	
}
</script>

When i load the page i see 2 images and after 1 second, it's working.

But it's only switch beetween default_img and first event image, i got several events with image in my table.

 

 

You can use ajax to call the same php code

I realy don't know how to do this.

Edited by raldje

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$rst = $bdd->query('SELECT image from matable order by Rand() LIMIT 0, 1');
while($donnees = $rst->fetch())
{
$image = nl2br($donnees['image']);
echo '<img src="defaultimg.jpg" alt="image_by_default" id="img1"/>';
echo '<img src="image/'.$donnees['image'].'" alt="image" id="img2"/>';
}
$rst->closeCursor();

<script>

var x=1;
        var myVar = setInterval(myTimer, 1000);

function myTimer() {
   if(x%2==0){
	document.getElementById("img1").style.display = "none";
	document.getElementById("img2").style.display = "block";
        x=1;
		}
	else{
	     document.getElementById("img2").style.display = "none";
	document.getElementById("img1").style.display = "block";
	x=2;
	}	
}
</script>

When i load the page i see 2 images and after 1 second, it's working.

But it's only switch beetween default_img and first event image, i got several events with image in my table.

 

 

You can use ajax to call the same php code

I realy don't know how to do this.

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Place all required code to produce random image using html img tag in a php file.

 

Look at this http://www.w3schools.com/ajax/tryit.asp?filename=tryajax_first you are basically replacing the paragraphs from the text file with your random img tag produced with your php file.

 

But instead running ajax code on button click you run it using setInterval.

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I'l try to explain with more precision.

In my table i have several entries of event, some with image, some without

I also have an image by default .

I try to make a header with all the present images in my table switching every 10 seconds, or my image by default if no event or only events without image.

Edited by raldje

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this code is help full to you check once

 

Initially you can save all images in one variable then,

 

$(document).ready(function()
{
window.setInterval(function(){
countdown();
}, 1000);// every one second
});

 

function countdown() {

// build your logic to get random images from that variable

}

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create php file that holds random image php script from database

 

random_image.php (note i created a quick connection to database images which is probably not setup as yours).

<?php

$db_host = 'host';
$db_user = 'user';
$db_pwd = 'password';

$database = 'whatever';


$bdd = new mysqli($db_host, $db_user, $db_pwd, $database);
// Check connection
if ($bdd->connect_error) {
    die("Connection failed: " . $bdd->connect_error);
}
$rst = $bdd->query('SELECT image from matable order by Rand() LIMIT 0, 1');

   while ($donnees = $rst->fetch()) {
    $image = nl2br($donnees['image']);
    if (empty($image)) {
        echo '<img src="imagedefaut.jpg" />';
    } else {
      
        echo '<img src="image/'.$donnees['image'].'" alt="image"/>';
    }
}
$rst->closeCursor();

Now we include this file in the page that uses this random image script to produce your current setup, this will always produce a random image on loading of page whether js disabled or not.

<!DOCTYPE html>
<html>
    <head>
        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
        <meta name="viewport" id="viewport" content="target-densitydpi=high-dpi,initial-scale=1.0,user-scalable=no" />
        <title>Ajax random image</title>
        <script type="text/javascript">

            window.onload = function() {

                window.setInterval(function() {
                    show_random_Image();
                }, 10000);
            }

            function show_random_Image() {
                var xhttp = new XMLHttpRequest();
                xhttp.onreadystatechange = function() {
                    if (xhttp.readyState == 4 && xhttp.status == 200) {
                        document.getElementById("random_image_wrap").innerHTML = xhttp.responseText;
                    }
                };
                xhttp.open("GET", "random_image.php", true); //note path to script may need amending
                xhttp.send();
            }
        </script>


        <style type="text/css">

        </style>
    </head>
    <body>
        <div id="random_image_wrap">
            <?php
            include ('/random_image.php'); // include random image script to you produce current random image effect note path to script may need amending
            ?>
        </div>

    </body>
</html>

Now the JavaScript ajax script will run at 10 sec interval on loading of page a connection to random_image.php it will retrieve the content produced by that php script and insert it into the element with id reference of 'random_image_wrap' overwriting the current image that is in there, without reloading of the page.

Edited by dsonesuk

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With php you could create a JavaScript array of all your images, then use JavaScript to select a random number between 0 and total number of images in array minus one (array index start at 0) then use this random number as a index ref of the image to use.

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Learn how to create a js array to store images, learn how to create a random number within a given range, then learn how to create JavaScript array using php to echo img files names into the js array.

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<?php
$stmt = $bdd->query('SELECT image FROM matable');
$donnees = $stmt->fetchAll();
var_dump($donnees);
$images = $donnees['image'];
echo '<img src="image/'.$images.'" id="my-image" />';
?>
  
<script type="text/javascript">
    var imgs = new Array(
        <?php
        for ($i = 0; $i < count($images); $i++) {
            echo '"'. htmlspecialchars($images[$i]) .'"';
            if ($i < count($images) -1) {
                echo ',';
            }
        }
        ?>
    );
    var position = 0;
    var taille = imgs.length;
    var image = document.getElementById('my-image');
    changeImage = function() {
        position = (position+1 >= taille) ? 0 : position+1;
        image.src = imgs[position];
        setTimeout(changeImage, 1000);
    }
    changeImage();
</script>

I think it's something like that but it don't work.

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Unless the image array img src contains the path also as in 'image/' it will replace img src with 'myimage.jpg' instead of 'image/myimage.jpg;

 

and shouldn't this

 

$donnees = $stmt->fetchAll();

 

be

 

$donnees = $stmt->fetch_all();

 

 

Also with the way you are accessing the img src it should be more like $images[$i][0] ?

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you can also use the image directory to lest images from

<div id="mypic"></div>
	 <script>
	   var myVar = setInterval(myTimer, 1000);
	  var images = [];
      <?php 
	  
	  // set $dir to your image directory
	  $dir = "./res/images/";

// Open a directory, and read its contents
if (is_dir($dir)){
  if ($dh = opendir($dir)){
    while (($file = readdir($dh)) !== false){
	 if (!is_dir($file))
	 {
	  ?>
	  //fill up the JS array with php values
	  images.push("<?php echo  $file; ?>");
	  
	 
	   <?php
	   }    
	}
    closedir($dh);
  }
}

  
?>

function myTimer() {
   var tt=Math.floor((Math.random() * images.length) + 1) - 1;
	document.getElementById("mypic").innerHTML  = "<img src='./res/images/" + images[tt] + "'>";
	
	
}
 
	 </script>
	 

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MySQLi uses fetch_all() while PDO uses fetchAll(). Personally, I prefer PDO.

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