Show/hide div with jQuery and AJAX not working properly - php

Question

I'm trying to show a specific div depending on the result of a SQL query.
My issue is that I can't get the divs to switch asynchronously.
Right now the page needs to be refreshed for the div to get updated.
<?php
//SQL query
if (foo) {
?>
<div id="add<?php echo $uid ?>">
<h2>Add to list!</h2>
</div>
<?php
} else {
?>
<div id="remove<?php echo $uid ?>">
<h2>Delete!</h2>
</div>
<?php
}
<?
<script type="text/javascript">
//add to list
$(function() {
$(".plus").click(function(){
var element = $(this);
var I = element.attr("id");
var info = 'id=' + I;
$.ajax({
type: "POST",
url: "ajax_add.php",
data: info,
success: function(data){
$('#add'+I).hide();
$('#remove'+I).show();
}
});
return false;
});
});
</script>
<script type="text/javascript">
//remove
$(function() {
$(".minus").click(function(){
var element = $(this);
var I = element.attr("id");
var info = 'id=' + I;
$.ajax({
type: "POST",
url: "ajax_remove.php",
data: info,
success: function(data){
$('#remove'+I).hide();
$('#add'+I).show();
}
});
return false;
});
});
</script>
ajax_add.php and ajax_remove.php only contain some SQL queries.
What is missing for the div #follow and #remove to switch without having to refresh the page?

Answer 1

"I'm trying to show a specific div depending on the result of a SQL query"
Your code doesn't seem to do anything with the results of the SQL query. Which div you hide or show in your Ajax success callbacks depends only on which link was clicked, not on the results of the query.
Anyway, your click handler is trying to retrieve the id attribute from an element that doesn't have one. You have:
$(".plus").click(function(){
var element = $(this);
var I = element.attr("id");
...where .plus is the anchor element which doesn't have an id. It is the anchor's containing div that has an id defined. You could use element.closest("div").attr("id") to get the id from the div, but I think you intended to define an id on the anchor, because you currently have an incomplete bit of PHP in your html:
<a href="#" class="plus" ?>">
^-- was this supposed to be the id?
Try this:
<a href="#" class="plus" data-id="<?php echo $uid ?>">
And then:
var I = element.attr("data-id");
Note also that you don't need two separate script elements and two document ready handlers, you can bind both click handlers from within the same document ready. And in your case since your two click functions do almost the same thing you can combine them into a single handler:
<script type="text/javascript">
$(function() {
$(".plus,.minus").click(function(){
var element = $(this);
var I = element.attr("data-id");
var isPlus = element.hasClass("plus");
$.ajax({
type: "POST",
url: isPlus ? "ajax_add.php" : "ajax_remove.php",
data: 'id=' + I,
success: function(data){
$('#add'+I).toggle(!isPlus);
$('#remove'+I).toggle(isPlus);
}
});
return false;
});
});
</script>

Answer 2

The way i like to do Ajax Reloading is by using 2 files.
The first: the main file where you have all your data posted.
The second: the ajax file where the tasks with the db are made.
Than it works like this:
in the Main file the user lets say clicks on a button.
and the button is activating a jQuery ajax function.
than the ajax file gets the request and post out (with "echo" or equivalent).
at this point the Main file gets a success and than a response that contains the results.
and than i use the response to change the entire HTML content of the certain div.
for example:
The jQuery ajax function:
$.ajax({
type: 'POST', // Type of request (can be POST or GET).
url: 'ajax.php', // The link to the Ajax file.
data: {
'action':'eliran_update_demo', // action name, used when one ajax file handles many functions of ajax.
'userId':uId, // Simple variable "uId" is a JS var.
'postId':pId // Simple variable "pId" is a JS var.
},
success:function(data) {
$("#div_name").html(data); // Update the contents of the div
},
error: function(errorThrown){
console.log(errorThrown); // If there was an error it can be seen through the console log.
}
});
The PHP ajax function:
if (isset($_POST['action']) ) {
$userId = $_POST['userId']; // Simple php variable
$postId = $_POST['postId']; // Simple php variable
$action = $_POST['action']; // Simple php variable
switch ($action) // switch: in case you have more than one function to handle with ajax.
{
case "eliran_update_demo":
if($userId == 2){
echo 'yes';
}
else{
echo 'no';
}
break;
}
}
in that php function you can do whatever you just might want to !
Just NEVER forget that you can do anything on this base.
Hope this helped you :)
if you have any questions just ask ! :)