applescript click link on website without id and without click at

I would click on a link at facebook present on this url https://www.facebook.com/events/birthdays/. enter image description here

I already test this code :

clickID("htb_more") to clickID(theId) --creates a function that we can use over and over again instead of writing this code over and over again

tell application "Safari" -- lets AppleScript know what program to controll

do JavaScript "document.getElementById('" & theId & "').click();" in document 1 -- performs JavaScript code that clicks on the element of a specific id

end tell -- tells Applescript you are done talking to Safari

end clickID -- lets AppleScript know we are done with the function

and others possibility on this location http://www.cubemg.com/how-to-click-a-button-on-a-web-page-with-applescript/

I know this code

click at {300, 100}

but I would not use click at because i want use my code on every computer.

Do you have other solution?

the next step of my code i already know it with your answer i could wish happy birthday to all my contact.