One thing that Kelly suggested to me earlier was to avoid the problem
altogether by eval()ing code that looks something like this:
"""
window.f0 = function() {
// ...
};
"""
Where "window" can be whatever scope you need to eval into. It's a little
long-winded (and I don't know what the performance impact might be), but it
should do the trick.
On Thu, Mar 5, 2009 at 5:20 PM, Ray Cromwell <[email protected]> wrote:
>
> There is also the magic eval() method in Firefox which allows an
> additional parameter to be specified as the context (see
> http://ajaxian.com/archives/evalfooa-objfn-how-you-arent-private-in-firefox
> )
>
> e.g.
>
> eval(script, $wnd);
>
> -Ray
>
>
> On Thu, Mar 5, 2009 at 2:10 PM, Matt Mastracci <[email protected]>
> wrote:
> >
> > Lex,
> >
> > Have you tried using the string constructor for Function()? I believe
> > that it creates a function whose lexical scope is bound to the top-
> > level, no matter where it is executed.
> >
> > <script>
> > var a = 2;
> >
> > function x() {
> > var a = 3;
> > return new Function("alert(a); a = 4;");
> > }
> >
> > x()();
> > alert(a);
> >
> > function y() {
> > var a = 10;
> > x()();
> > }
> > y();
> > </script>
> >
> > This alerts "2", "4", "4" in Firefox, Safari, Opera and IE6.
> >
> > On 5-Mar-09, at 1:19 PM, Lex Spoon wrote:
> >
> >>
> >> For possible amusement, I spent half a day yesterday spelunking into
> >> the world of various ways to install code in a web browser. Details
> >> are here:
> >>
> >>
> http://lexspoon.blogspot.com/2009/03/many-scopes-of-javascripts-eval.html
> >>
> >>
> >> My initial idea to use window.eval turns out to be terribly
> >> non-portable: it only evaluates at window scope on Firefox. Instead,
> >> I'm thinking to use the following code to install newly downloaded
> >> code:
> >>
> >> if (window.execScript) {
> >> window.execScript(script)
> >> } else {
> >> var tag = document.createElement("script")
> >> tag.type = "text/javascript"
> >> tag.text = script
> >> document.getElementsByTagName("head").item(0).appendChild(tag)
> >> }
> >>
> >>
> >> The first branch is for window.execScript, which is available on IE
> >> and, of all things, Chrome. They are such similar browsers, you know.
> >> The second branch works on all browsers, but it's ugly enough that I
> >> didn't want it to be used all the time. Maybe that's silly, and only
> >> the second branch should always be used.
> >>
> >> Any thoughts or better ideas?
> >>
> >> Lex
> >>
> >> >
> >
> >
> > >
> >
>
> >
>
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