open拒绝访问

JScript code

window.onload = initPage;function initPage() {  document.getElementById("username").onblur = checkUsername;  document.getElementById("register").disabled = true;}function checkUsername() {  document.getElementById("username").className = "thinking";  request = createRequest();  if (request == null)    alert("Unable to create request");  else {    var theName = document.getElementById("username").value;    var username = escape(theName);    var url= "submit.aspx?username=" + username;    request.onreadystatechange = showUsernameStatus;    request.open("GET", url, true);    request.send(null);  }}

到open拒绝访问 怎么解决额

[解决办法]
alert(url)看看这个网址有没有错，参数都传进来没有？
再来判断是js出问题了，还是submit.aspx出问题了