property theSender : missing value
property thePath : missing value
property theSearchString : missing value
property loadDone : false –original was "webFrame"
property aWebView : missing value

set aPath to (POSIX path of (path to desktop)) & ((current application’s NSUUID’s UUID()’s UUIDString()) as string) & ".webarchive"
set archRes to archivePageToPath("https://www.apple.com/jp/shop/browse/home/specialdeals/mac", aPath, "Mac mini", me, 10) of me

on archivePageToPath(thePageURL, aPath, searchString, sender, timeoutSec)
　　–Check If this script runs in foreground
　　if not (current application’s NSThread’s isMainThread()) as boolean then
　　　　display alert "This script must be run from the main thread (Command-Control-R in Script Editor)." buttons {"Cancel"} as critical
　　　　error number -128
　　end if
　　
　　set my theSender to sender — store main script so we can call back
　　set my thePath to aPath — store path for use later
　　set my theSearchString to searchString — store for use later
　　set my aWebView to missing value
　　set my loadDone to false
　　
　　— make a WebView
　　set theView to current application’s WebView’s alloc()’s initWithFrame:{origin:{x:0, y:0}, |size|:{width:100, height:100}}
　　
　　— tell it call delegate methods on me
　　theView’s setFrameLoadDelegate:me
　　
　　— load the page
　　theView’s setMainFrameURL:thePageURL
　　
　　–wait for download & saving
　　repeat timeoutSec * 10 times
　　　　if my loadDone is not equal to false then
　　　　　　exit repeat
　　　　end if
　　　　delay 0.1
　　end repeat
　　if my loadDone = false then return "timed out"
　　
　　
　　— the main frame is our interest
　　if (my loadDone) = aWebView’s mainFrame() then
　　　　
　　　　— get the text of the page
　　　　set theText to ((my loadDone)’s DOMDocument()’s documentElement()’s outerText())
　　　　
　　　　— search it
　　　　if (theText’s rangeOfString:theSearchString)’s |length|() > 0 then
　　　　　　
　　　　　　— get the data and write it to file
　　　　　　set theArchiveData to (my loadDone)’s dataSource()’s webArchive()’s |data|()
　　　　　　theArchiveData’s writeToFile:thePath atomically:true
　　　　　　
　　　　　　— tell our script it’s all done
　　　　　　return "The webarchive was saved"
　　　　else
　　　　　　return "Seach string not found"
　　　　end if
　　end if
　　
end archivePageToPath

— called when our WebView loads a frame
on WebView:curWebView didFinishLoadForFrame:webFrame
　　set my loadDone to webFrame
　　set my aWebView to curWebView
end WebView:didFinishLoadForFrame:

— called when there’s a problem
on WebView:WebView didFailLoadWithError:theError forFrame:webFrame
　　— got an error, bail
　　WebView’s stopLoading:me
　　set my loadDone to false
　　error "The webarchive was not saved"
end WebView:didFailLoadWithError:forFrame: