hiding a div from users view - php

Question

I want to return true when the number of rows in a table is more than one and show a div with jquery as shown in the jquery code .In addition return false when the number of rows is zero and hide a div as shown in the code below.The php code is executing and returning a correct value but the jquery code is neither showing or hiding a div.I need to show a div when the value returned is true and hide a div when the value returned is false;
**php code** php code for retrieving the number of rows from a table
<?php
require'php/connection.php';//a file for connecting to the database
$user_name=getUserField('user_name');//function for getting the name of the user in session
$query="select `order_id` from `inbox` where `buyer_name`='$user_name'";
$query_run=mysql_query($query);
$num_rows=mysql_num_rows($query_run);
if($num_rows >= 1) {
return true;
} else if($num_rows == 0) {
return false;
}
?>
jquery code Jquery code for either hiding or showing a div
$(document).ready(function() {
$.post('php/ManNotify.php',{},function(data){
if(true) {
$('#notify').show();
} else if(false) {
$('#notify').hide();
}
});
});

Answer 1

Do you realize your if statement reads,
if(true) ..
else if(false) ...
The hide will never execute. Is this your problem?

Answer 2

When using AJAX calls with PHP, you should echo the value rather than return it. Modify your PHP code like so:
<?php
require'php/connection.php';//a file for connecting to the database
$user_name=getUserField('user_name');//function for getting the name of the user in session
$query="select `order_id` from `inbox` where `buyer_name`='$user_name'";
$query_run=mysql_query($query);
$num_rows=mysql_num_rows($query_run);
if($num_rows >= 1){
echo json_encode(array("status" => true));
} else if($num_rows == 0) {
echo json_encode(array("status" => false));
}
exit;
?>
You'll also need to modify your JavaScript accordingly. Right now, if(true) will always execute on the return. Modify it like so:
// Shorthand for $(document).ready
$(function(){
$.post('php/ManNotify.php',{}, function(data) {
// JavaScript truthy/falsy will take care of the statement
if(data.status) {
$('#notify').show();
} else {
$('#notify').hide();
}
});
});
EDIT:
As #mplungjan points out in the comments below, the JavaScript could be simplified in the callback to be the following: $('#notify').toggle(data.status);. The resulting JavaScript would be:
// Shorthand for $(document).ready
$(function(){
$.post('php/ManNotify.php',{}, function(data) {
$('#notify').toggle(data.status);
});
});
Thanks to #mplungjan for the suggestion.

Answer 3

$(document).ready(function(){
$.post('php/ManNotify.php',{},function(data){
if(data == 'true'){
$('#notify').show();
}else if(data == 'false')
{
$('#notify').hide();
}
});
});

Answer 4

There are two problems with your code:
The server-side code. Returning boolean TRUE or FALSE this way will only render the page blank.
The jQuery code logic is wrong: if(true){ case will always be executed (because the value is, well, always true).
A very simple fix would be (untested):
if($num_rows >= 1){
echo 'true';
} else {
echo 'false';
}
Then, in the JS:
$.post('php/ManNotify.php', function(data){
if(data === 'true'){
$('#notify').show();
} else {
$('#notify').hide();
}
});
Note that this is not optimized.

Answer 5

$(document).ready(function(){
$.post('php/ManNotify.php',{},function(data){
if(data == "true"){
$('#notify').show();
}else if(data == "false")
{
$('#notify').hide();
}
});
});