why doesn't 'do javascript' call in Applescript execute when the same code typed into browser does?

Question

I\'m trying to figure out why my Applescript does nothing when the same javascript code typed into a Safari location bar works.

Go to a search results page, such as:

Answer 1

The problem is that do JavaScript has to correctly address a tab in a Safari window.

The following script works for me, if the search results page is the current tab in the frontmost Safari window:

tell application "Safari"
    activate
    set theScript to "document.getElementsByClassName('vspib')[0].click();"
    do JavaScript theScript in current tab of first window
end tell