javascript xmlhttprequest无法正常工作
[英]javascript xmlhttprequest won't work
问题描述
I'm learning javascript for a new project. 
我正在为一个新项目学习javascript。 I have seen many tutorials about javascript and xmlhttprequest, but when I try to run decode it won't work. 我看过许多关于javascript和xmlhttprequest的教程，但是当我尝试运行解码时，它将无法正常工作。 can somebody help me. 有人可以帮我吗
here is my html+javascript code: 这是我的html + javascript代码：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>xml reader</title> </head> <body> <script type="text/javascript"> var xmlhttp; var xmldoc; if(window.XMLHttpRequest){ xmlhttp = new XMLHttpRequest(); }else {// code for IE6, IE5 xmlhttp=new ActiveXObject("Microsoft.XMLHTTP"); } xmlhttp.onreadystatechange=stateChange(); xmlhttp.open("GET","info.xml",true); xmlhttp.send(null); xmldoc = xmlhttp.responceXML.documentElement; document.write(xmlhttp.getElementsByTagName("vakken")[0].childNodes[0].nodeValue); </script> </body> </html>
here is my xml file: 这是我的xml文件：
<?xml version="1.0" encoding="utf-8"?> <info> <name>test</name> <nummber>10</nummber> </info>
4 个解决方案
解决方案1
1 2010-11-10 06:54:02
You have a ReferenceError in your JavaScript that prevents it from executing completely. 您的JavaScript中有一个ReferenceError，它阻止它完全执行。 "stateChange" is undefined. “ stateChange”未定义。 You need to define the stateChange function. 您需要定义stateChange函数。
Also it looks like "response" is spelled wrong (responce). 而且看起来“响应”的拼写错误（响应）。
Please go through this tutorial from W3Schools: http://www.w3schools.com/XML/xml_http.asp 请从W3Schools阅读本教程： http : //www.w3schools.com/XML/xml_http.asp
You're very close so use W3Schools as a resource to fix up some other problems in your code. 您非常接近，因此可以使用W3Schools作为资源来修复代码中的其他问题。
解决方案2
1 已采纳 2010-11-10 06:58:32
maybe you should use xmlhttp.onreadystatechange and set it to a real function. 也许您应该使用xmlhttp.onreadystatechange并将其设置为实函数。 the function stateChange() does not exist in the above example. 上面的示例中不存在stateChange（）函数。
a good working example that does almost the same thing as you do is here: http://www.w3schools.com/ajax/tryit.asp?filename=tryajax_first 一个与您做的几乎相同的工作示例，在这里： http : //www.w3schools.com/ajax/tryit.asp?filename=tryajax_first
解决方案3
1 2010-11-10 07:22:21
stateChange() that you call onreadystatechange is not defined - add a function named stateChange that will be called once the response returns. 未定义您在onreadystatechange上调用的stateChange() -添加一个名为stateChange的函数，一旦响应返回，该函数将被调用。
An example of such a function: 此类功能的示例：
function stateChange() {
if(xmlhttp.readyState == 4){
xmldoc = xmlhttp.responseXML.documentElement;
document.write(xmlhttp.getElementsByTagName("vakken")[0].childNodes[0].nodeValue);
}
}
You must remember that AJAX is asynchronous - the response must be handled separately at the time it returns - hence the readystatechanged event usage... 您必须记住AJAX是异步的-响应返回时必须单独处理-因此readystatechanged事件用法...
Remove the two lines after sending the request from your original code (they are in the stateChange function). 从原始代码发送请求后删除两行（它们在stateChange函数中）。
解决方案4
1 2010-11-10 08:02:14
Are you don't receiving an answer in the Request or may it be the case, that you get an answer but it's not written into your dom? 您是否没有在请求中收到答案，或者是这样，您得到了答案但没有写到您的dom中？ Lately I had the problem, that document.write wouldn't work in one of my pages. 最近，我遇到了问题，那个document.write在我的其中一个页面中不起作用。 I found out, that document.write is not allowed in XHTML-based pages (My page was XHTML 1.1, yours is XHTML 1.0). 我发现，在基于XHTML的页面中不允许document.write （我的页面是XHTML 1.1，您的页面是XHTML 1.0）。 So this is just a guess. 所以这只是一个猜测。 You could test this with the firebug-extension for firefox. 您可以使用firebug扩展的firebug进行测试。 Althought all common browsers respect, that document.write is not allowed and throw a error-message, IE does however support document.write in any case... 尽管所有常见浏览器都尊重该document.write ，但不允许该document.write并引发错误消息，但是IE在任何情况下均支持document.write ...
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