How do I scroll to the top of a window using applescript? - applescript

Question

I want applescript to scroll a window all the way up.
I've tried the page up key, the home key, and I've tried looking for a way to scroll using the built in scrolling capabilities of the window, but I've so far been unable to even move the scrolled position at all.

Answer 1

Basically, use a tell app "System Events" statement to send keystrokes and key codes.
In theory, you could use the following:
keystroke page up key
keystroke page down key
keystroke home key
But for me this doesn´t work. The good news is that you can use the key codes instead. I suggest using the excellent free Full Key Codes application to read them, though it is a bit tricky to let it read two keys pressed simultaneously.
The key codes for the fn+ arrow keys-combos are as following:
Page up: fn+ up key: key code 116
Page down: fn+ down key: key code 121
Home: fn+ left key: key code 115
End: fn+ right key: key code 119
So for example if you had a long page open in Safari, and you want to scroll to its end, use
tell application "System Events"
tell application "Safari" to activate
— to see the animation, we wait a moment:
delay 0.5
key code 119
end tell

Answer 2

With browsers you could also use JavaScript:
tell application "Safari" to tell document 1
do JavaScript "window.scroll(0,0)"
end tell
tell application "Google Chrome" to tell active tab of window 1
execute javascript "window.scroll(0,0)"
end tell

Answer 3

The alternative to sending keystrokes is to use GUI scripting.
Caveat: While GUI scripting is more robust than sending keystrokes for a given version of an application, changes in the application's layout in future versions can break your code.
Also:
GUI scripting requires that access for assistive devices be enabled; enabling requires admin privileges:
up to 10.8, this could be done programmatically, system-wide by executing tell application "System Events" to set UI elements enabled to true (required admin privileges)
Sadly, on 10.9+, this no longer works, and apps must be authorized manually, individually - the system will prompt you on first run (requires admin privileges)
however, in both scenarios tell application "System Events" to get UI elements enabled will report whether access is enabled or not.
Determining the right UI element targets can be non-trivial and tedious; using the Accessibility Inspector utility that comes with Xcode helps. The class names reported by this utility correspond to the UI element classes contained in the System Events dictionary; e.g., AXSplitGroup corresponds to splitter group.
The following scrolls Safari 6.0.3's front window to the top (access for assistive devices must be enabled):
tell application "System Events"
# Use Accessibility Inspector to find the desired target.
tell front window of process "Safari"
tell scroll bar 1 of scroll area 1 of group 1 of group 1 of last group
set value of attribute "AXValue" to 0 # Scroll to top.
end tell
end tell
end tell
Update: As a reminder that this type of scripting works well for a given version of an application, the code had to be changed for Safari 8.0.4:
tell application "System Events"
# Use Accessibility Inspector to find the desired target.
tell front window of process "Safari"
tell scroll bar 1 of scroll area 1 of group 1 of group 1 of group 2
set value of attribute "AXValue" to 0 # Scroll to top.
end tell
end tell
end tell