a xmlhttprequest.send() crash in javascript_问答_开发者

a xmlhttprequest.send() crash in javascript

开发者 https://www.devze.com 2023-02-13 12:15 出处：网络

I was trying to learn XmlHttpRequest. I followed this W3School Tutorial. in the file httprequest.0.js:

I was trying to learn XmlHttpRequest. I followed this W3School Tutorial.

in the file httprequest.0.js:

function myHttpRequestFunction()
{
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
  xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
  xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}

alert("A"); 
xmlhttp.open("GET","httprequest.0.xml",false);
alert("B"); 
xmlhttp.send(); // never succeeds this line !
alert("C");
xmlDoc=xmlhttp.responseXML; 
alert("D");

}

Everything seems to break at that line: xmlhttp.send();

are there exception catchers in Javascript or anything so as to manage开发者_运维知识库 such crash ? maybe xmlhttprequest states ?

in the file httprequest.0.html:

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
    <!-- Scripts -->
    <script type="text/javascript" src="httprequest.0.js"></script>
</head>
<body onload="myHttpRequestFunction()">
    <h3>XMLHttpRequest</h3><p>
    <div id="RequestContent"> </div>    
</body>
</html>`

in the file httprequest.0.xml: