JavaScript XMLHttpRequest发送失败

Question

I try to make an AJAX requestin Chrome using the following code:

var url = "http://" + document.domain + "/status_data.lua?resetsessiontimeout=false";
xmlhttp.open("GET", url, true);
xmlhttp.send(null);

Using WireShark is see that send doesn't send anything... There is no GET emitted. But if I add an & at the end of the URL:

var url = "http://" + document.domain + "/status_data.lua?resetsessiontimeout=false&";
                                                                                   ^

then send will emit the GET request.

Is this expected?

Answer 1

I'm going to guess a couple of common errors people (and I) have made.

1. Did you create an instance of xmlhttp? In otherwords, do you have a line before your code above that has "var xmlhttp = new XMLHttpRequest();" (case sensitive)

2. Are you testing this through a file (like C:/test.html) or on a webserver (like Apache or jboss)? If you do the former, you'll get a Cross Point Origin error and doing the latter will fix it.

3. Are you sure the server code is not looking for additional variables after resetsessiontimeout? Because the '&' is used to delimit additional variables. Although I'm pretty sure it was unneeded to end a variable.

Like if I wanted to send an error string with that url. I can do resetsessiontimeout=false&errmsg=test