Set checkbox state after ajax query - php

Question

Depending on the value in the mysql database I would like a checkbox to be either checked or unchecked. Although the ajax query is getting the correct value the checkbox always remains checked
The Jquery
<script type="text/javascript">
$(document).ready(function() {
$.ajax({
type: "POST",
url: "ajax/get_db_settings.php",
dataType: "json",
data: 'user='+1,
success:function(response){
var taken_by_on = response.taken_by;
alert(taken_by_on);
if(taken_by_on = 0){
$('.taken_by_input').attr('disabled',true).css('color','#F0F0F0');
$('#taken_by_enable').prop('checked', false);
}else if(taken_by_on = 1){
$('.taken_by_input').attr('disabled',false).css('color','#000');
$('#taken_by_enable').prop('checked', true);
}
},error:function (xhr, ajaxOptions, thrownError){
alert(thrownError);
}
});
});
</script>
get_db_settings.php
$user_id = $_POST['user'];
$sql = "SELECT * FROM user WHERE userID = $user_id";
$result = mysqli_query($mysqli,$sql) or die(mysqli_error($mysqli));
if($result){
$row = mysqli_fetch_array($result);
$taken_by_on = $row['takenByOn'];
$output_array = array(
'taken_by' => $taken_by_on
);
}
echo json_encode($output_array);
The html
<form name="add_positioning" class="postable" id="add_positioning">
<table border="0" class="autoTable_pos">
<tr>
<td colspan="2" style="text-align:left">Enable <input style="width:10px"
type="checkbox" name="taken_by" id="taken_by_enable">
</td>
</tr>
<?
$sql= "SELECT * FROM gradeReason WHERE reason_userID = $id AND category = 'positioning' AND current = 1 ORDER BY reasonID";
$result = mysqli_query($mysqli,$sql) or die(mysqli_error($mysqli));
while($row = mysqli_fetch_array($result)){?>
<tr>
<td>
<input type="text" class="taken_by_input outline ie7_td"
name="reason[][<? echo $row['reasonID']; ?>]" value="<? echo $row['reason_name']; ?>"/>
</td>
<td><input type="button" name="delete_pos" value=""
class="taken_by_input delRow_pos del_reason_btn del_taken_in"
onClick="UpdateRecord(<? echo $row['reasonID']; ?>);"/>
</td>
</tr>
<?
}
?>
</table>
</form>
The plan is that if the value in the database is 1 the checkbox is checked and the inputs in the table are enabled whereas they would be disabled and the checkbox would remain unchecked if the value was 0.
I am using an array to pass back the values from the Ajax because I intend to add more to it once I have this working

Answer 1

In the if condition, you need to use == not =, = is the assignment operator, you need the equals operator which is ==
if (taken_by_on == 0) {
$('.taken_by_input').attr('disabled', true).css('color', '#F0F0F0');
$('#taken_by_enable').prop('checked', false);
} else if (taken_by_on == 1) {
$('.taken_by_input').attr('disabled', false).css('color', '#000');
$('#taken_by_enable').prop('checked', true);
}