Lost connection does not return error with jQuery AJAX on live site but on dev? - asp.net

Question

I am using the following code to post data from a asp.net 2.0 site to an asp.net 2.0 web service that post the data to a server:
$.ajax({
type: "POST",
url: "SynchroniseCustomers.asmx/synchroniseCustomers",
data: JSON.stringify(customerObj),
contentType: "application/json; charset=utf-8",
dataType: "json",
error: function (xhr, status) {
// If not successfull
},
success: function (msg) {
deleteCustomer(customer.id);
}
});
I have a JavaScript function to check if I have connection or not, if I have I run the synchronisation (pulling data from web kit browser local database):
function checkConnection() {
var i = new Image();
i.onload = synchronise;
i.onerror = fail;
i.src = 'http://myurl.com/ping.gif?d=' + escape(Date());
setTimeout("checkConnection()", 60000); // Execute every minute
}
Thing is, if I run this locally and drop my internet connection the web service returns a 500 error (like I want it to do) and deleteCustomer(customer.id); is not called. However, on the live site if I drop my connection the web service does not return an error and deleteCustomer(customer.id); is called even if I don't have a connection to the internet (customer gets deleted from local database without being posted to the web server).
What's the reason for this? Please let me know if you need more code.
Thanks in advance.

Answer 1

You probably didn't wait a minute after dropping the connection.

Answer 2

There is a case that Ajax recall the cached data when you are ask for delete, and even if you are not connected to the net its get it from cache, so thats why its think that is all ok. The cache on jQuery Ajax is true by default.
So try with cache:false
$.ajax({
type: "POST",
url: "SynchroniseCustomers.asmx/synchroniseCustomers",
data: JSON.stringify(customerObj),
contentType: "application/json; charset=utf-8",
dataType: "json",
cache:false,
error: function (xhr, status) {
// If not successfull
},
success: function (msg) {
deleteCustomer(customer.id);
}
});
For the image call, its better to use Interval and not create memory again and again.
<img id="PingerImg" width="1" height="1" src="/spacer.gif?" onload="synchronise" onerror="fail" />
<script language="javascript" type="text/javascript">
var myImg = document.getElementById("PingerImg");
if (myImg){
window.setInterval(function(){myImg.src = myImg.src.replace(/\?.*$/, '?' + Math.random());}, 60000);
}
</script>
Update
The other solution is to really get a confirmation code form the server that you have delete the user, and only if you read that code , proceed to delete the user on remote.
success: function (msg) {
if(msg.confirm = true)
{
deleteCustomer(customer.id);
}
else
{
alert('Fail to delete user.');
}
}