问题
<head runat="server">
<script type ="text/javascript">
function LoadXMLDoc()
{
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("Div1").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","ajax_info.txt",true); //this text file is in the same folder
xmlhttp.send();
}
</script>
<body>
<form id="form1" runat="server">
<div id="Div1"><h2>How Ajax works</h2></div>
<button type="button" onclick="LoadXMLDoc()">Change Content</button>
</form>
</body>
回答1:
try this alert(xmlhttp.responseText); to see if you are actually getting any value for responseText, or better yet to make sure you are actually getting to that code block
来源：https://stackoverflow.com/questions/4200645/why-isnt-this-ajax-code-showing-any-output-in-asp-net