IE为什么无法识别AJAX调用中返回的JavaScript代码？

Question

I have a (hopefully) simple question.

I'm using ajax to update a DIV on my current page. Within what's being inserted into the div is a script block that defines a variable. Within FF, I can access the variable, but IE doesn't see the var. Do I need to eval the returned code in some way for IE to recognize the variable?

As a simple example, if my ajax call returns this snippet of code and gets inserted into the div, I get an alert in FF but not in IE:

<script language='JavaScript' type='text/JavaScript'> alert('Foo!'); </script>

Answer 1

是的，常见的解决方法是使用getElementsByTagName()获取所有script元素，然后对它们进行eval() 。

Answer 2

You should return a JSON object as the result of the AJAX call and then use the json2.js Javascript stuff to evaluate it into a live object.

http://json.org/ has a link to JSON libraries for every language known to man, including Javascript.

Answer 3

The problem might be your JavaScript MIME type - you're using an unconventional type (type='text/JavaScript'):

<script language='JavaScript' type='text/JavaScript'> alert('Foo!'); </script>

You should try this instead:

<script type='text/javascript'> alert('Foo!'); </script>

I ran some tests recently and found that even modern browsers are pretty picky about this MIME type (skip to Additional Test #1), and will refuse to execute the JavaScript if it isn't set correctly: http://davidbcalhoun.com/2010/what-happens-when-we-serve-javascript-with-random-mime-types

If that's not the issue, try adding the script to the document Head:

document.getElementsByTagName('head')[0].appendChild(script);

This is what Google Analytics did until recently, so I would be surprised if it didn't work for you. You shouldn't need to use eval().

According to this page this page , IE is picky with nodes that haven't yet loaded, but the Head is almost guaranteed to have loaded, which is why it shouldn't have the same issue.