Trying to read styleSheets returns undefined

I've searched for an answer and no solution seems to fix this problem, so hopefully stating it specifically will help me find a solution.

I'm trying to read cssText of the first stylesheet using document.styleSheets[0].cssText, but it always returns undefined. I do have a stylesheet and it's visibly noticeable, but JavaScript doesn't seem to recognize it.

This did, however, work when I included the stylesheet within the page using <style>. I don't see why this would change when usin开发者_JAVA百科g <link>, though. Not only is it placed before the script, but it even returns undefined when using javascript:alert(document.styleSheets[0].cssText) in the omnibar after the page is fully loaded.

Thanks for any help.

Edit: This applies to any method with document.styleSheets[0], including those of which are supposed to work on multiple browsers and have worked for me prior to using <link>. For example: document.styleSheets[0].cssRules[0].selectorText

According to quirksmode.org, document.styleSheets[n].cssText is only supported in IE.

The form

document.styleSheets[n].cssRules[m].cssText

seems to be more widely supported, so you could just loop over that and build a string from the individual rules. (Although you have to replace cssRules with rules for IE).

I thing that this answer is out of time, but it could be useful for someone else. The result can be "undefined" due 2 different reasons:

a) In some browsers, the property "cssRules" does not work (in accord with http://www.javascriptkit.com/domref/cssrule.shtml, only for supported in NS/ Firefox). For the other browser, you should use the property "rules", instead.

You can solve the problem using something like:

if (document.styleSheets[0].cssRules)
    crossrule=document.styleSheets[0].cssRules[0]
else if (document.styleSheets[0].rules)
    crossrule=document.styleSheets[0].rules[0]

to extract the rule and, afterwards, to extract the name of selector:

document.styleSheets[0].cssRules[0].selectorText

b) After the overpassing of the issue a), you may have another problem: The rules that starts with a @, like @import of @font-face, as considered as rules. However, their "selectorText" is undefined. So, you must have a way of skip them. I am working on it, right now. But I have not found yet a solution. Anyway, it is an help to know way it is happening.

Hope this helps