Function not returning newest variable

Here's the deal: I want my doAjaxRequest function to open a CFM file, which then calls a function in a CFC file depending on the ?functions= url. Well, everything works perfectly, except result. The particular thing I'm doing is when a user is typing in a desired username, onkeyup calls this function which then makes a database query to see if the username is already taken. The thing is, inside the onreadystatechange function, result is updated as intended, but when i get out of that, and return result, it's always one result behind.

For example, they type in "test", but "test" is taken. But, instead of it returning false when they type the second "t", it says true. But if I backspace or type another letter, it will say false. The same is for the very first keystroke, except instead of saying true, it will return undefined(null, i suppose).

Any ideas?

Code:

---

var result;
function doAjaxRequest(type, functions, location)
{
        aXmlHttp.open(type, "/ajax/ajax.cfm?"+functions, true);
        aXmlHttp.onreadystatechange =
        function()
        {
                if (aXmlHttp.readyState == 4)
                {
                        if (aXmlHttp.responseText)
                        {
                                var a = aXmlHttp.responseText;
                                if(location != null)
                                {
                                        document.getElementById(location).innerHTML = a;
                                }
                                else
                                {
                                        result = a;
                                }
                        }
                }
        };
        aXmlHttp.send(null);
       
        return result;
}

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Well, first off there is an AJAX forum. I will have a moderator move it there.

Quote:

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Originally Posted by Psytherium

it's always one result behind.

---

Sounds to me like you are experiencing something similar to JavaScripts onkeypress vs. onkeyup.

Is this the same thing you are battling?

Code:

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This is one behind when typing.
<input type="text" onkeypress="alert(this.value)">
This is on time.
<input type="text" onkeyup="alert(this.value)">

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EDIT: Well, I took a glance at the AJAX forum and saw a thread that talked about SJAX(SynchronousJAX), so I gave it a try and it works. Trying to learn client-side coding, server-side coding, and conventions like AJAX all at the same time is pretty difficult, ahhh.

Perhaps it is a onkeyup/onkeypress problem. I tried changing my
document.getElementById("username").onkeyup = validateUsername
to
document.getElementById("username").onkeypress = validateUsername,

and now when I type in the username textbox, nothing happens. I did run this test:

Code:

---

var testResult = 0;
function testResultF()
{
        document.onkeyup =
        function()
        {
                var a = testResult + 1;
                testResult = a;
                document.getElementById("test").innerHTML = testResult;
                document.getElementById("test").innerHTML += a;
        }
       
        return testResult;
}

---

The code above returns one value behind.

Code:

---

var testResult = 0;
function testResultF()
{
        document.onkeypress =
        function()
        {
                var a = testResult + 1;
                testResult = a;
                document.getElementById("test").innerHTML = testResult;
                document.getElementById("test").innerHTML += a;
        }
       
        return testResult;
}

---

The code above returns the proper result.

I just don't see why if inside the nested function testResult prints out the desired value, why it isn't returned.

Quote:

---

Originally Posted by Psytherium

I just don't see why if inside the nested function testResult prints out the desired value, why it isn't returned.

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Well, in your examples, the return call is not inside the function that contains the variable to be returned.

Quote:

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Originally Posted by peejavery

Well, in your examples, the return call is not inside the function that contains the variable to be returned.

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But if the variable is global, should it not matter? Or is java script different than other programming languages in that sense?

I guess I have never fully tested it.