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Document.links empty after calling document.close

Answer 1

A:

As I said in a comment, this is a very strange issue. But I think it happens because the inclusion of an external script causes a delay in page rendering (of the new page) and its DOM might not be ready to inspect.

My suspicion is supported by the fact that adding the (new) defer attribute seems to solve this issue:

This Boolean attribute is set to indicate to a browser that the script is meant to be executed after the document has been parsed.

The defer attribute can be set on the original page, as you want an exact copy of it. You can set it if it doesn't matter where a script is being included (e.g., when using document.write in your included file it does matter at which place you include it).

As defer is a Boolean attribute, it is activated when it is simply present (defer) or (when using XHTML) set to itself (defer="defer"). In your case, the script inclusion would read:

<script type="text/javascript" src="some.js" defer></script>

Update regarding your update: you should still insert a Doctype in the main page (consider using the HTML 5 one).

And I think the way you attached your onload event is the best you can do.

But considering the goal you want to achieve (a print preview without hyperlinks): you can also use the "print" media attribute and style hyperlinks like text; that's way more easy than the thing you are doing and it works when JavaScript is disabled.

Marcel Korpel 2010-08-28 17:05:56

To start many thanks for the good advice! I have rewritten the example. See in further post. One question: how I understand defer='true': this will execute the script after the document is fully build up. But where do you set it then? It must be set inside the html of the popup (adding a script as string in the html you pass with write function)? Where this is very similar to putting the call to reportLinks inside a function registered as onload handler for the popup window. But how can onload listener be registered for popups (hopefully browser indep.) Thanks again!

Marcel 2010-08-28 18:54:46

@Marcel: I updated my answer. Regarding the `onload` event of popups: as you're merely creating a new window, it has its own DOM and its own `onload` event. E.g., if it's defined in your some.js, the onload handler will be triggered on the main window, as well as on the newly created window.

Marcel Korpel 2010-08-28 19:18:51

Thanks, now I see: defer for included script. Look at my extended question. There you can see what I mean with onload for the popup.

Marcel 2010-08-28 19:43:15

Answer 2

A:

The only way I could make the example above work portable over Firefox, Chrome and IE is by registering the onload listener through inlined JavaScript in the HTML loaded in the popup window. Following example code shows how.

<html>
 <head>
  <script type="text/javascript" src="script.js"></script>
 </head>
 <body>
  <p><a href="javascript: openWindow()">Open Same Content and Show Links Report</a></p>
  <p><a href="javascript: reportLinks(document.links)">Show Links Report</a></p>
 </body>
</html>

This page uses a script in script.js file. Following shows the content of that file.

function openWindow(){
  var w = window.open('', 'otherWin', 'width=600,height=600');
  w.document.write(
    '<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"&gt;\n&lt;html&gt;\n'+
    document.getElementsByTagName("html")[0].innerHTML+
    '\n <script type="text/javascript">\n'+
    '  function addOnloadListener(listener){\n'+
    '    if (window.addEventListener) {\n'+
    '      window.addEventListener("load", listener, false);\n'+
    '    } else {\n'+
    '      window.attachEvent("onload",listener);\n'+
    '    }\n'+
    '  }\n'+
    '  addOnloadListener(function(){reportLinks(document.links);});\n'+
    ' </script>\n'+
    '</html>');
  w.document.close();
}

function reportLinks(links){
  var report = 'links: '+links.length;
  for (var i=0;i<links.length;i++){
    report += '\n (link='+links[i].href+')';
  }
  alert(report);
}

When putting the function addOnloadListener directly in the JavaScript file (not inlined in the page) it doesn't work in IE6 because, I believe, it cannot handle the order of script entries correctly. When addOnloadListener was not inlined the inlined call to addOnloadListener didn't work, it simply couldn't find the function in the earlier:

<script type="text/javascript" src="script.js"></script>

The code is only a simple example that doesn't really do a lot. I used it for disabling all links in a print preview popup page.

A simpler way to register an onload listener for a popup window portable over browser is always welcome.

Thanks, Marcel

Marcel 2010-09-06 22:43:40

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Document.links empty after calling document.close

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