使用 javascript 从 PDF 获取信息（标题、主题、作者、制作人...）
我试图学习如何在 pdf 文件中使用 javascript，以及如何从 /Info 对象中获取信息，例如作者和标题。我发现了两种在 pdf 中使用 js 的方法，并且我整理了 2 个示例，第一个有效，第二个无效。它们都执行 javascript，但第二个代码无法访问 /Info 数据。我不明白为什么。
示例 1（此代码显示带有 /Title 内容的警报，工作正常）：
%PDF-1.3
1 0 obj
<</Type/Catalog/Pages 5 0 R/OpenAction 3 0 R>>
endobj
2 0 obj
<<
/Producer (test)
/Subject (test)
/Title (test)
>>
endobj
3 0 obj
<</Type/Action/S/JavaScript/JS 4 0 R>>
endobj
4 0 obj
<</Length 17>>
stream
app.alert(title);
endstream
endobj
5 0 obj
<<
>>
endobj
xref
trailer
<<
/Root 1 0 R
/Info 2 0 R
>>
startxref
%%EOF
示例 2（此代码不显示任何警报，但如果我用字符串替换标题，它确实显示了警报）；
%PDF-1.3
1 0 obj
<</Type/Catalog/Pages 5 0 R/AcroForm 3 0 R>>
endobj
2 0 obj
<<
/Producer (test)
/Subject (test)
/Title (test)
>>
endobj
3 0 obj
<</XFA [4 0 R]>>
endobj
4 0 obj
<</Length 767>>
stream
<?xml version="1.0" encoding="UTF-8" ?>
<xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/">
<config xmlns="http://www.xfa.org/schema/xci/1.0/"><present>
<pdf><interactive>1</interactive><version>1.6</version>
</pdf><xdp><packets>*</packets></xdp><destination>pdf</destination></present></config>
<template xmlns="http://www.xfa.org/schema/xfa-template/2.5/">
<subform layout="tb" locale="en_US" name="form">
<subform>
<field>
<event activity="initialize" name="eventName">
<script contentType="application/x-javascript">
app.alert(title)
</script>
</event>
</field>
</subform>
</subform>
</template>
<xfa:datasets xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/">
<xfa:data></xfa:data></xfa:datasets>
</xdp:xdp>
endstream
endobj
5 0 obj
<<
>>
endobj
xref
trailer
<<
/Root 1 0 R
/Info 2 0 R
>>
startxref
%%EOF
（两个 pdf 源都不是真正有效的 pdf，但 js 被执行，我删除了很多内容以使它们更易于阅读）
有人知道为什么吗app.alert(title) 没有处理第二个样品？
Im trying to learn how to use javascript inside pdf files, and how to grab information from the /Info object like author and title. I've found two ways to use js inside a pdf, and I've put together 2 samples, the first works, the second doesn't. They both execute javascript, but the second code can't access the /Info data. I can't figure out why.
Sample 1 (This code shows an alert with the contents of /Title, works fine):
%PDF-1.3
1 0 obj
<</Type/Catalog/Pages 5 0 R/OpenAction 3 0 R>>
endobj
2 0 obj
<<
/Producer (test)
/Subject (test)
/Title (test)
>>
endobj
3 0 obj
<</Type/Action/S/JavaScript/JS 4 0 R>>
endobj
4 0 obj
<</Length 17>>
stream
app.alert(title);
endstream
endobj
5 0 obj
<<
>>
endobj
xref
trailer
<<
/Root 1 0 R
/Info 2 0 R
>>
startxref
%%EOF
Sample 2 (this one doesn't show any alert, but if i replace title with a string, it does show the alert);
%PDF-1.3
1 0 obj
<</Type/Catalog/Pages 5 0 R/AcroForm 3 0 R>>
endobj
2 0 obj
<<
/Producer (test)
/Subject (test)
/Title (test)
>>
endobj
3 0 obj
<</XFA [4 0 R]>>
endobj
4 0 obj
<</Length 767>>
stream
<?xml version="1.0" encoding="UTF-8" ?>
<xdp:xdp xmlns:xdp="http://ns.adobe.com/xdp/">
<config xmlns="http://www.xfa.org/schema/xci/1.0/"><present>
<pdf><interactive>1</interactive><version>1.6</version>
</pdf><xdp><packets>*</packets></xdp><destination>pdf</destination></present></config>
<template xmlns="http://www.xfa.org/schema/xfa-template/2.5/">
<subform layout="tb" locale="en_US" name="form">
<subform>
<field>
<event activity="initialize" name="eventName">
<script contentType="application/x-javascript">
app.alert(title)
</script>
</event>
</field>
</subform>
</subform>
</template>
<xfa:datasets xmlns:xfa="http://www.xfa.org/schema/xfa-data/1.0/">
<xfa:data></xfa:data></xfa:datasets>
</xdp:xdp>
endstream
endobj
5 0 obj
<<
>>
endobj
xref
trailer
<<
/Root 1 0 R
/Info 2 0 R
>>
startxref
%%EOF
(Both pdf sources are not really valid pdfs but the js gets executed, i removed a lot of stuff to make them easier to read)
Does someone knows why app.alert(title) doesn't work on the second sample?
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评论（2）
app.alert(event.target.title);app.alert(event.target.title);这确实是一条评论，但出于格式和可读性原因，我使用答案。
http://corkami.googlecode.com/svn-history/r503/wiki /PDFTricks.wiki
如果您有
/Info <>那么你可以做
app.alert(info.author + info.title + info. Producer);在你的情况下，我猜你需要获取文档你排在第一位。我怀疑你能做你想做的事，因为你似乎在 pdf 中嵌入了 xml 文件。我没想到它会起作用
This is really a comment, but I use answer for formatting and readability reasons.
http://corkami.googlecode.com/svn-history/r503/wiki/PDFTricks.wiki
If you have
/Info <</Author(Hello) /Title( World) /Producer( !)>>then you can do
app.alert(info.author + info.title + info.producer);In your case I would guess you need to get the document you are in first. I doubt you can do what you want since you seem to be embedding an xml file inside the pdf. I would not expect it to work