Help with Ajax..

[jboesch]

Hi all! Could anyone tell me why this wont work...
The function works when i remove the (ver) after "stateChanged" (inside showCat function). What I'm doing is I want to use this function more than once, so Im combining PHP to throw in a variable in showcat(str,ver). The ver is where the integer goes and auto-increments using a for loop that is being called through PHP
This is my PHP... (which works fine)..

<select name="blah" onchange="showCat(ver,$i)">
<option>blah</option>
</select>

... however the ajax wont work!

Please help!

<script type="text/javascript">
var xmlHttp

function showCat(str,ver)
{
xmlHttp=GetXmlHttpObject()
if (xmlHttp==null)
{
alert ("Browser does not support HTTP Request")
return
}
var url="getcat.php"
url=url+"?id="+str
xmlHttp.onreadystatechange=stateChanged(ver)
xmlHttp.open("GET",url,true)
xmlHttp.send(null)
}

function stateChanged(ber)
{
if (xmlHttp.readyState==4 || xmlHttp.readyState=="complete")
{
document.getElementById("txtHint"+ber).innerHTML=x mlHttp.responseText
}
}

function GetXmlHttpObject()
{
var objXMLHttp=null
if (window.XMLHttpRequest)
{
objXMLHttp=new XMLHttpRequest()
}
else if (window.ActiveXObject)
{
objXMLHttp=new ActiveXObject("Microsoft.XMLHTTP")
}
return objXMLHttp
}
</script>

[Kravvitz]

Welcome to SitePoint Forums, jboesch.

To answer your question, I suggest you read this.

[jboesch]

Thanks, but it didn't really help me

I want to use this function again and again and display the text in a diff element each time.. eg. txtHint1, txtHint2, txtHint3.. thats why im adding +ber to getElementByID("txtHint"+ber);

[Kravvitz]

That explained that this:

xmlHttp.onreadystatechange=stateChanged(ver)

should be this:

xmlHttp.onreadystatechange=function(){stateChanged(ver)}

That's not your only problem though. You don't seem to realize that the number outputted by the PHP will only be incremented when the page reloads.

I am concerned that your code may not be following JavaScript Best Practices. I recommend you read up on them.

[jboesch]

I didn't post all of my PHP, but it works fine. The AJAX was my difficulty, I'm pretty new to it. I grabbed this code from a tutorial, but with that added suggestion you made, it all works!

Thank you very much!