Reliable “Wait for Safari to Load a Page” Strategies?

Question

Reliable “Wait for Safari to Load a Page” Strategies?

I've just started trying to write my first script which interacts with Safari, and have been looking through the Safari dictionary for something I can test to determine if a page has finished loading. I have a lot of trouble with app dictionaries, so I hope this isn't too trivial.

Let's say I have a Safari browser window open with id winID, and a tab in it with index tabIndex. I want to load a web page and get the source HTML. This seems to work (most of the time):

tell application "Safari" to tell window id winID to tell tab tabIndex
set URL to someURL
delay 30
set someHTML to source
end tell

Two problems: (1) most of the time it's unnecessarily dismally slow, and (2) it's still dangerous, if the server is really backed up it can still fail, and I may find my script reading the previous page, or possibly a partial page. It would be nice if tabs or windows had some sort of "busy" property I could test in a delay loop, but if they do I'm missing it in the dictionary. Any ideas for replacing my "delay 30" statement with something better?

Dual 1.2 GHz, Mac OS X (10.5.5)

Posted on Nov 29, 2008 1:15 PM

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Answer 1

red_menace

Level 6

17,066 points

Nov 29, 2008 3:14 PM in response to Jeff Johnson 1

This old Apple webpage has some routines that use Safari's do javascript command. The first is one that determines if a page is loaded, with a maximum time to wait.

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Answer 2

Arkouda

Level 4

3,377 points

Nov 30, 2008 10:37 AM in response to Jeff Johnson 1

Here's an example of the Javascript approach:

--your set URL
delay 3 -- this is a delay to allow the page to start loading
--wait till it's loaded
set pageLoaded to false -- this initialises the pageLoaded variable that gets set below
repeat while not pageLoaded -- keep doing this loop until loading complete
if (do JavaScript "document.readyState" in document 1) is "complete" then
set pageLoaded to true
else
delay 3 -- you can try adjusting this delay
end if
end repeat
--your set someHTML ...

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Answer 3

Nov 30, 2008 2:45 PM in response to Arkouda

Thanks to you both. That old Apple page was surprisingly helpful on a number of questions. For example, I didn't know I could use Do JavaScript to extract links from a page. I had another way of doing this, but it was comparatively clumsy. On the question I asked, I was up most of last night experimenting, and the JavaScript method works well. There is still a slight problem with one site I use where the login page instantly loads another, which loads yet another before finally loading the home page (and why site designers make things so difficult I don't know), but an initial delay of 3-4 seconds seems to take care of it, and I think I have a handle on things now. Thanks again.

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