问题
I noticed that my Javascript bookmarklet was failing on certain sites like Google Reader and Google search results pages (and randomly on some non-Google sites). Looking at the console, I could see that, for these pages, clicking the bookmarklet did not append elements to the head/body like it normally did, but created a new document that looked like this:
<html>
<head></head>
<body></body>
</html>
Even when I reduced my bookmarklet to javascript:alert(window.location.href); it would create this blank page and run the bookmarklet therein, so that the alert showed about:blank. On most sites, this blank page is not created and the correct location is shown.
Can someone explain this? Are these sites sandboxing externally run code as a safety measure?
UPDATE: I currently can't reproduce this on browsers other than Chrome 17.0.932.0 dev. Please let me know if anyone else can reproduce these results on Chrome or otherwise.
回答1:
I think this is a bug in Google Chrome, I've filed it to their bug database: https://bugs.webkit.org/show_bug.cgi?id=72606
回答2:
You need to ensure that the topmost code, i.e. the one right after javascript: does not return anything.
Usually this is done by wrapping everything in void():
javascript:void(alert(window.location.href));
It's very odd that it breaks with alert() though since the function itself doesn't return anything...
回答3:
If a javascript: url returns a string it will be used to create a new document:
javascript:'foo bar baz';
This can be a tough issue to debug if you don't know to watch out for it. It can crop up if you use a function that returns a string or end your bookmarklet with a line that sets a string value:
javascript: a = prompt('foo bar baz'); b = a;
A simple solution is to use a closure:
javascript:(function(){ var a; a = prompt('foo bar baz'); window.b = a}());
An alternative is to end with void 0;
javascript: a = prompt('foo bar baz'); b = a; void 0;
来源：https://stackoverflow.com/questions/8107036/javascript-bookmarklet-fails-on-certain-sites-creates-ghostly-new-html-page