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Dustin Scott
Courses Plus Student 7,819 PointsCheck if check box is checked using PHP and AJAX
Hi I am trying to know whether the checkbox is checked so I can display a message and if not another message will got displayed. I tried several times and it didn't work. It will just alert True when I check and uncheck.
AJAX code:
$('#check').click(function(){
var check= $(this).val();
$.ajax({
url: './opt/index_opt.php',
type: 'POST',
data: {check:check},
success: function(data){
alert(data);
}
});
});
This is my PHP file:
<?php
session_start();
include "../db.php";
$user= $_SESSION['id'];
if(isset($_POST)){
$check = $_POST['check'];
if(isset($check)){
echo 'True';
}else{
echo 'False';
}
}
?>
7 Answers
Michael Collins
433 PointsOkay, here's a working example. The first part is the HTML page with the form and the JavaScript.
<html>
<head>
<title>Untitled Document</title>
<script language="javascript" src="https://code.jquery.com/jquery-1.11.1.min.js" type="text/javascript"></script>
<script language="javascript" type="text/javascript">
send_data = function(name) {
$.ajax({
url: "/test/index.php",
dataType: "json",
data: {'name' : name},
type: "POST",
cache: false
}).done(function(data, status, xml) {
var obj = jQuery.parseJSON(data);
alert(obj.success);
}).fail(function(jqXHR, textStatus, errorThrown) {
}).always(function() {
});
}
$(document).ready(function() {
$("#myform").submit(function() {
var cb = $("input#firstname");
if (cb.is(":checked")) {
send_data(cb.val());
} else {
alert("not sending data - box is not checked");
}
return false;
});
});
</script>
</head>
<body>
<form id="myform" action="">
Check this box if your first name is Fred:
<input type="checkbox" id="firstname" name="firstname" value="Fred" />
<input type="submit" value="Submit" />
</form>
</body>
</html>
The second part is the PHP script.
<?php
if ($_SERVER['REQUEST_METHOD'] === 'POST') {
if (isset($_REQUEST['name'])) {
# Append something onto the $name variable so that you can see that it passed through your PHP script.
$name = $_REQUEST['name'] . ' - 123 ';
# I'm sending back a json structure in case there are multiple pieces of information you'd like
# to pass back.
header('Content-Type: application/json');
print json_encode('{"success" : "' . $name . '"}');
}
}
exit;
?>
Michael Collins
433 PointsI wonder if you are using "check" a few too many times. You are initializing it as a variable but then also using is an object property. I'm thinking you could either change the name of the value your are retrieving from "check" to value. OR, you could enclose the data object in quotes, like this
data:{"check":check}
Try changing your value name so as to clarify which variable is holding which data and see if that doesn't move you farther along.
$('#check').click(function(){
var value= $(this).val();
$.ajax({
url: './opt/index_opt.php',
type: 'POST',
data: {check:value},
success: function(data){
alert(data);
}
});
});
Dustin Scott
Courses Plus Student 7,819 PointsI tired it, it didn't work
Michael Collins
433 PointsAh, the checkbox always has the same value, whether it's checked or not.
I think you want to check whether the check box is checked. var value = $('#checkbox').is(':checked');
$('#check').click(function(){
var value= $(this).is(':checked');
$.ajax({
url: './opt/index_opt.php',
type: 'POST',
data: {check:value},
success: function(data){
alert(data);
}
});
});
Dustin Scott
Courses Plus Student 7,819 PointsWhen I added $(this).is(':checked'); It just displays false.
Michael Collins
433 PointsWould you display your HTML code too please?
Dustin Scott
Courses Plus Student 7,819 Points<input type="checkbox" name="check" id="check" checked >
Michael Collins
433 Pointsisset() returns TRUE when a variable exists even if the value it holds is empty -> "" it only returns false when the value is set to NULL. NULL is not the same as empty.
You don't have to put a value in the checkbox, but if you don't I believe it is by default the integer 1. So, your HTML means you assigned a value of 1. And, in PHP, 1 is the same as TRUE.
<input type="checkbox" name="check" id="check" check="checked" value="1">
Once you assigned $check = $_POST['check'], you ended up setting $check to the empty set "" which isset() will return true.
Try this ...
<?php
session_start();
include "../db.php";
$user= $_SESSION['id'];
if(isset($_POST)){
$check = $_POST['check'];
if($check == 1){
echo 'True';
}else{
echo 'False';
}
}
?>
Dustin Scott
Courses Plus Student 7,819 PointsIt still only shows false. Really thank you for trying to help me
Michael Collins
433 PointsAlright, I'll get back to you tomorrow. I thought I could just glean real quick what's going on but I'm obviously flubbing it. I'll have time tomorrow morning to make a working example. So, if someone else hasn't given you some direction by then, I'll get back to you.
Dustin Scott
Courses Plus Student 7,819 PointsOkay no problem thank you
Dustin Scott
Courses Plus Student 7,819 PointsDustin Scott
Courses Plus Student 7,819 PointsNow its working thank you :)