t1.htm

ajax的例子

<script language="javascript" type="text/javascript">
var xmlHttp = false;
try {
  xmlHttp = new ActiveXObject("Msxml2.XMLHTTP");
} catch (e) {
  try {
    xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
  } catch (e2) {
    xmlHttp = false;
  }
}
if (!xmlHttp && typeof XMLHttpRequest != 'undefined') {
  xmlHttp = new XMLHttpRequest();
}

function callServer() {
  var u_name = document.getElementById("u_name").value;
  if ((u_name == null) || (u_name == "")) return;
  var url = "cu.asp?name=" + escape(u_name);
  xmlHttp.open("GET", url, true);
  xmlHttp.onreadystatechange = updatePage;
  xmlHttp.send(null);  
}

function updatePage() {
  if (xmlHttp.readyState < 4) {
	test1.innerHTML="loading...";
  }
  if (xmlHttp.readyState == 4) {
    var response = xmlHttp.responseText;
	test1.innerHTML=response;
  }
}
</script>


<form name="form1" action="t1.asp" method="post" autocomplete="off">
用户名: <input type="text" name="u_name" id="u_name" onChange="callServer();" />
 <span id="test1">是否能注册</span><br>
密 码：<input type="password" />
 <input type="submit" value="注册" />
</form>