I am getting Notice: Undefined index: select_dept when using ajax call - php

Question

i want to display doctors name corresponding to the speciality so i have used ajax
when speciality is selected corresponding doctors name will also display
i am getting error like this and doctors list is not showing up
Notice: Undefined index: select_dept in C:\wamp\www\xx\get_specialist.php
on line 2
Call Stack
# Time Memory Function Location
1 0.0012 140616 {main}( ) ..\get_specialist.php:0
my form code
<select name="select_dept" id="select_dept"
class="textBox" style="width:180px" onChange="getSpecialist(this.value)">
<option value="">Select Department</option>
<?php
include("db_conexn.php");
$res=mysql_query("SELECT * FROM imh_departments");
while($rowCat2 = mysql_fetch_array($res)){?>
<option value="<?php echo $rowCat2['depart_id']?>">
<?php echo $rowCat2['department_name'];?></option>
<?php }?>
</select>
<div id="statediv">
<select name="doct" >
<option>Select Doctor</option>
</select>
</div>
My ajax code
<script language="javascript" type="text/javascript">
function getXMLHTTP() { //function to return the xml http object
var xmlhttp=false;
try{
xmlhttp=new XMLHttpRequest();
}
catch(e) {
try{
xmlhttp= new ActiveXObject("Microsoft.XMLHTTP");
}
catch(e){
try{
xmlhttp = new ActiveXObject("Msxml2.XMLHTTP");
}
catch(e1){
xmlhttp=false;
}
}
}
return xmlhttp;
}
function getSpecialist(countryId)
{
var strURL="get_specialist.php?country="+countryId;
var req = getXMLHTTP();
if (req){
req.onreadystatechange = function() {
if (req.readyState == 4) {
// only if "OK"
if (req.status == 200)
{
document.getElementById('statediv').innerHTML=req.responseText;
} else {
alert("Problem while using XMLHTTP:\n" + req.statusText);
}
}
}
req.open("GET", strURL, true);
req.send(null);
}
}
get_specialist.php code
<?php
$country=$_REQUEST['select_dept'];
include("db_conexn.php");
$query="SELECT doct_id,doct_name FROM imh_doctors WHERE depart_id='$country'";
$result=mysql_query($query);
?>
<select name="doct" >
<option>Select Doctor</option>
<?php while ($row=mysql_fetch_array($result)){?>
<option value=<?php echo $row['doct_id'];?>><?php echo $row['doct_name'];?></option>
<?php } ?>
</select>

Answer 1

your
$country=$_REQUEST['select_dept'];
should be
if(isset($_REQUEST['country'])) {
$country=$_REQUEST['country'];
// rest of db code
}
Please note that your code is open to SQL injection and should use mysqli and mysqli_real_escape_string instead.

Answer 2

You are assigning $country to select_dept and you may want to change that.
$country = $_REQUEST['country'];