I am forced to use a web application written (over a decade ago I'm guessing) for IE6 and only works with IE (newer versions in quirks mode). I have been able to repair some of the more egregious javascript with a Safari extension that injects scripts to detach event handlers and replace them with DOM compliant versions.
I am now turning my attention to annoyances rather than the downright broken. The heavy handed use of alerts to inform the user of progress is painful. I thought it would be a fairly nice addition to my extension to override the window.alert function with some css popovers, but the challenge I am having is with pages that are sent back after an http post, where the first thing they do is display a success (or failure) alert.
According to this Apple documentation "a Start Script executes when the document has been created but before the webpage has been parsed". I would have thought that if the page hadn't been parsed, the scripts in the page's body's script tags wouldn't run, but this is not the behaviour I am seeing. Instead, it appears that any scripts in the page returned from the post response execute before my start script even loads.
To test this I have a very simple start script that logs to the console location.href and tries to replace window.alert with console.log.
The injected start script:
console.log(window.location.href + "loaded killAlert.js") ;
window.alert=function(str) { console.log(str) ; }
The test web page:
<html><head></head>
<body>
<script>alert("this is an alert message") ;</script>
nothing to see here... move along.
</body>
</html>
What happens is that when loading a test page with a script embedded, the alert executes before anything is written to console.log.
My questions—
- When do start scripts actually get called?
- Is there any way I can get them to execute before any scripts on the page?
While this seems like it should be fairly straight forward, but so far I haven't been able to find a way around the problem through reading documentation, search or experimenting. I'm hoping someone else has solved something similar.
Try calling it anonymously, it will execute the script immediately after the creation. Hope it helps.