[webkit-dev] why js script" var a = new XMLHttpRequest; ", it's ok; but "var a = new StyleSheet; ", it'll throw an exception?

[Nevo]

hi:
I havn't used the StyleSheet object like in this way ,so here's my guess :
The stylesheet is usually defined in server side ,people usually retrieve
stylesheet via DOM StyleSheetObject (document.styleSheets). If you wanna
create a new StyleSheet in your javascript. you probably may look at this
http://eightpence.com/creating-new-css-stylesheets-with-javascript/

Nevo


2009/6/5 Suk Zhong <sukmaillist at gmail.com>

> Hi All:
>    We're trying to extend WebKit dom js binding.We have some questions.
>
>    in DOMWindow.idl having the following code:
>    attribute StyleSheetConstructor StyleSheet;
>    attribute [JSCCustomGetter] XMLHttpRequestConstructor XMLHttpRequest;
>
>    and we find class JSXMLHttpRequestConstructor has function
> getConstructData, while JSStyleSheetConstructor doesn't have function
> getConstructData.
>
>    if test the following js script:"var a = new XMLHttpRequest;", it's
> ok;but "var a = new StyleSheet;", it'll throw an exception.
>
>    and we trac this problem to Interpreter::privateExecute() and
> JSValuePtr::getConstructData function
>
>    inline ConstructType JSValuePtr::getConstructData(ConstructData&
> constructData)
>    {
>         return JSImmediate::isImmediate(asValue()) ? ConstructTypeNone :
> asCell()->getConstructData(constructData);
>    }
>    and we know this function returns ConstructTypeNone for
> JSStyleSheetConstructor object,  ConstructTypeHost for
> JSXMLHttpRequestConstructor object;
>
>    JSStyleSheetConstructor object and JSXMLHttpRequestConstructor object
> are returned by the same template function getDOMConstructor.
>
>    our questions are:
>
>    1.why it has this return?
>    2.which codes make the two object have different immediate value?
>    3.some people can explain the whole role of class JSImmediate?
>    4.our trac maybe be not correct,who can explain why newing StyleSheet
> has exception and newing XMLHttpRequest is OK?
>
> Thanks and Best Regards
>
> Suk
>
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