Ajax function partially fails when alert removed
- by YsoL8
Hello.
I have a problem in the following code:
//quesry the db for image information
function queryDB (parameters) {
var parameters = "p="+parameters;
alert ("hello");
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)
{
// use the info
alert (xmlhttp.responseText);
}
}
xmlhttp.open("POST", "js/imagelist.php", true);
//Send the proper header information along with the request
xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xmlhttp.setRequestHeader("Content-length", parameters.length);
xmlhttp.setRequestHeader("Connection", "close");
xmlhttp.send(parameters);
}
When I remove the alert statement 4 lines down I hit problems. This function is being called by a loop, and without the alert, I only get results for the last value sent to the statement. With it, I get everything I was expecting and really I'm at a loss to know why.
I've heard that this may be a timing issue as I'm sending new requests before the old one is finished. I also heard polling being mentioned, but I can't find any information detailed enough.
I'm new to synchronous services and I'm not really aware of the issues.
