Question

like this is my form’s select box

<select name="cutid" onchange="findcustid(this.value)">
<option value="1001">cust 1</option>
<option value="1002">cust 2</option>            
<option value="1003">cust 3</option>            
</select>

now i have this ajax code which is passing and fill some select boxes

function findcustid(custid) {
    var custid = custid;
}

function Inint_AJAX() {
    try {
        return new ActiveXObject("Msxml2.XMLHTTP");
    } catch (e) {} //IE
    try {
        return new ActiveXObject("Microsoft.XMLHTTP");
    } catch (e) {} //IE
    try {
        return new XMLHttpRequest();
    } catch (e) {} //Native Javascript
    alert("XMLHttpRequest not supported");
    return null;
};

function dochange(src, val) {
    var req = Inint_AJAX();
    req.onreadystatechange = function () {
        if (req.readyState == 4) {
            if (req.status == 200) {
                document.getElementById(src).innerHTML = req.responseText; //retuen value
            }
        }
    };
    req.open("GET", "podetfill.php?data=" + src + "&val=" + val + "&custid=" + custid); //make connection
    req.setRequestHeader("Content-Type", "application/x-www-form-urlencoded;charset=iso-8859-1"); // set Header
    req.send(null); //send value
}
window.onLoad = dochange('proid', -1); // value in first dropdown

on this line

req.open("GET", "podetfill.php?data="+src+"&val="+val+"&custid="+custid);

of above code i’ve added +"&custid="+custid this but its not pass value of custid on podetfill.php page and getting error

Error: custid not defined

Answer 1

You cannot use your method for the following reasons :

• the var custid is declared within a function – so its only accessible within that function
• Even if the var custid was declared a global you still couldn’t use it as the AJAX gets executed using the window.load event meaning the select.change event wouldnt have been fired yet

One solution would be to get the value of the select before using it :

var cus = document.getElementById('custid');
var custid = cus.options[cus.selectedIndex].value;
req.open("GET", "podetfill.php?data=" + src + "&val=" + val + "&custid=" + custid); //make connection

you also need give the select an id attribute to use this code :

<select id="custid" name="cutid" onchange="findcustid(this.value)">