Insert MySQL record with PHP and AJAX - php

Question

trying to insert a record in my DB using AJAX for the very first time. I have the following...
Form
<form>
<input type="text" id="salary" name="salary">
<input type="button" onclick="insertSalary()">
</form>
AJAX
<script type="text/javascript">
function insertSalary()
{
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById('current-salary').innerHTML=xmlhttp.responseText;
}
};
xmlhttp.open("POST","insert_salary.php",true);
xmlhttp.send("salary=" + document.getElementById("salary").value);
}
</script>
PHP
$uid = $_SESSION['oauth_id'];
$monthly_income = mysql_real_escape_string($_POST['salary']);
#Insert a new Record
$query = mysql_query("INSERT INTO `income` (user_id, monthly_income) VALUES ($uid, '$monthly_income')") or die(mysql_error());
$result = mysql_fetch_array($query);
return $result;
Nowmy data is being inserted into the table BESIDES the 'salary' which is being inputted as '0'
Once inserted I also have a div 'current-salary' that should then be populated with there inputted value only it isnt, Can anybody help me to understand where im going wrong?

Answer 1

If you want to save your self a lot of time, effort, and heartache, use the jquery library for your ajax requests. You can download it at http://jquery.com/
After adding a reference(Script tag) to the jquery script your javascript for the ajax request would become:
function insertSalary()
{
var salary = $("#salary").val();
$.post('insert_salary.php', {salary: salary}, function(data)
{
$("#current-salary").html(data);
});
}
Also keep in mind that using "insert_salary.php" as the url means it is a relative path and must be in the folder of the current running script.
Your php script needs to echo whatever you would like to be injected into your current-salary tag also.