写了个最简单的ajax：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Simple XMLHttpRequest</title>
<script type="text/javascript">
var xmlHttp;
function createXMLHttpRequest() {
if (window.ActiveXObject) {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
}
else if (window.XMLHttpRequest) {
xmlHttp = new XMLHttpRequest();
}
}
function startRequest() {
createXMLHttpRequest();
xmlHttp.onreadystatechange = handleStateChange;
xmlHttp.open("GET", "simpleResponse.xml", true);
xmlHttp.send(null);
}
function handleStateChange() {
if(xmlHttp.readyState == 4) {
if(xmlHttp.status == 200) {
alert("The server replied with: " + xmlHttp.responseText);
}
else
alert(xmlHttp.statusText);
}
}
</script>
</head>
<body>
<form action="#">
<input type="button" value="Start Basic Asynchronous Request" onclick="startRequest();"/>
</form>
</body>
</html>
为什么单击button后，alert出来的是0啊，也就是status是0，我的simpleRequest.xml和这个html是放在同一目录下的啊？