How to refresh specific div using Javascript/Jquery with the variables on it

You can execute an ajax call:

function ajaxCall() {
    $.ajax({
        method: 'POST',
        url: 'path/to/asyncHalndler.php',
        data: { ... },
        success: function (data) {
            if (data) {
                $('#salary').html(data);
            }
        }
    });
}

// Execute ajax call every 5 seconds
setInterval(function() {
    ajaxCall();
},5000);

var salary = document.getElementById('salary');

Now, the value of your variable salary will be the DOM node where you would like to change the value. When you get new data, you can refresh text inside your p tag with salary id by adding salary.innerText = yourNewValue;

This is pure JavaScript way of updating that element with id.

You will need an jquery ajax call for that. first you should create php file get_salary.php where you send id from jquery ajax if you want to update the salary for unique id:

in get_salary.php you need to get salary from database so the code in this php file will be like that

$id = $_POST['ID']
$query = mysql_query("SELECT * FROM sallaries WHERE id='$id'") or die("Can't connect");
$fetch = mysql_fetch_array($query)
$salary = $fetch['salary']
echo $salary

after that you will need javascript file(e.g script.js) from where you will send the request and id to the get_salary.php and grab the data from it, after that you will be able to update salary in html, so code in javascript file will be like that:

function updateSalary(){}
var id=25;
$.ajax({
    url: "get_salary.php",
    type: 'POST',

    //sending id
    data:'id='+id,
    success: function(result){

        //updating html
        $("#salary").html(result);
    }
});
}

//setting interval to update in every second
setInterval(updateSalary, 1000)

so it will update your salary in the div

It's better to use ajax way. But if u are looking for a very simple solution then jQuery .load will be the best

setInterval($("#salary").load("<url to get the value>"), 1000);