if statement in success ajax - php

Question

I'm having trouble implementing if statement in ajax success function.
<?php
include('../Config/config.php');
$myquery = "SELECT * FROM voters WHERE Precinct = '".$_POST['precinct']."'";
$execute = mysqli_query($mysqli, $myquery);
if (mysqli_num_rows($execute) >= 1)
{
echo "Precinct is full.\n Recheck precinct number.";
}
?>
function checkerprecinct() {
var precinct = $("#precinct").val();
$.ajax({
type: "POST",
url: "precinctchecker.php",
data: "precinct=" + precinct,
success: function(data) {
console.log(data);
if (data === "") {
alert("Data is empty!");
} else {
alert(data);
}
}
});
}
I would like to use this as a validation.
I want to alert the user if the sent data contains similar data from the database.

Answer 1

try this code
change with your code
PHP Code:
$data = array();
if (mysqli_num_rows($execute) >= 1)
{
$data= array('code'=>100,'message'=>"Precinct is full.\n Recheck precinct number.");
//echo "Precinct is full.\n Recheck precinct number.";
}else{
$data= array('code'=>101,'message'=>"Data is empty!");
}
echo json_encode($data);
exit;
ajax code:
var data = JSON.parse(data);
if (data['code'] == 100) {
alert(data['message']);
}