检查是否在PDF中打开了JavaScript对话框

Question

I'm trying to make a pair of dialog boxes that show upon opening a PDF; one dialog will show if the PDF is opened in a reader that supports Adobe Reader's level of JavaScript functionality, and the other will show if the previous dialog is not shown (ie, if the PDF is opened in a reader with little JavaScript support, which means the first dialog cannot be shown).

The problem I'm running into right now is trying to get the second dialog to show. I tried using a try-catch, but I'm assuming it didn't work because the first dialog box didn't actually fail to show... or something.

So how would I go about showing the second dialog if the first is not shown due to a lack of support?

Here's my current code (which is written as a "page open" action in the page properties):

try {
     var d = dialog();

     d.execDialog();
} catch (e) {
     app.alert("ERROR: Incompatible reader; please install Adobe Reader to open this file.");
}

function dialog()
{
     var dialogDescriptor =
    {
        // Dialog description goes here
    };

     var dialogObject =
    {
        execDialog: function() { return app.execDialog(dialogDescriptor); },
    };

 return dialogObject;

}

The reason I'm using app.execDialog is because there will be hyperlinks in the first dialog box.

Also, I'm completely new to using JavaScript and working with PDFs, so I apologize if this is a dumb question.

Answer 1

You can check to see if the PDF viewer supports the Dialog object by testing if app.execDialog is a function. Something like this...

if (typeof app.execDialog === "function") {
    // Can show Acrobat dialogs    
}
else {
    // Can't show Acrobat Dialogs
}  

That kind of code works for any function or object method.